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  • 51.
    Ataniyazov, Ataniyaz
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Underhållsarbete på krafttransformator: En studie på genomförande av underhållsarbete i transformatoranläggningen med optimeringsförslag.2014Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
  • 52.
    Ayubi, Shir Mohammad
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Modifiering av klaffskopa på uppdrag av Swekip Sweden AB2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a Bachelor thesis in Mechanical Engineering as a result of work situated at Swekip AB Sweden in spring 2015. The work was about reconstructing of an existing snow clearing bucket which is assembly designed in software Inventor and the product manufactures in China.Snow clearing bucket and the other parts in term of wear steels would be reconstructed and they had to follow Swedish and European standard in terms of bushing, wear resistance steel etc.The manufacturing company in China does not have the same technical possibilities as a Swedish manufacturing company. For example sheet metal bending, laser cuttings machine etc.Therefore wishes the company that the new design of snow clearing bucket leads to a simple documentation/construction design which in turn make it easier for the manufacturer production.

  • 53.
    Azizi, Shoaib
    et al.
    Umeå University.
    Nair, Gireesh
    Umeå University.
    Olofsson, Thomas
    Umeå University.
    Comparative Study of Influential Factors on Implementation of Energy Efficiency Measures in Single-Family Houses in Cold Climate2018Conference paper (Refereed)
    Abstract [en]

    A combination of factors, which include occupants and building related aspects, could motivate homeowners to implement energy renovation (ER). This study applies a comparative approach to assess perspectives of single-family homeowners towards different energy efficiency measures (EEMs). The aim is to unveil the factors that are effective on the residents’ attitude and decision making to implement an EEM or a set of EEMs. The analysis is based on a questionnaire survey conducted during spring 2017 among1550 owners of single-family houses in seven municipalities in northern Sweden. Approximately, 35% of respondents expressed their interest to install energy efficient household appliances and solar photovoltaic (PV) systems. The analysis suggests significant relations between the homeowners’ interest to implement thermal envelope measures and the quality of the house such as age and indoor environmental problems such as cold surfaces. The group of respondents, who reported their heating cost to be high, are more likely to be interested in implementing thermal envelope measures than other measures such as HVAC. Several socio-economic factors are found to be significantly related with homeowners’ interest to implement EEMs.

  • 54. Backman, Anders
    et al.
    Bodin, Kenneth
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Lacoursière, Claude
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Servin, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Democratizing CAE with Interactive Multiphysics Simulation and Simulators2012Conference paper (Other academic)
  • 55.
    Backman, Fredrick
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Från föhn till feu!: Esrange och den norrländska rymdverksamhetens tillkomsthistoria från sekelskiftet 1900 till 19662010Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This essay is about the origin, planning and establishment of the European Space Research Organisation's (ESRO) sounding rocket base Esrange outside Kiruna in Northern Sweden. Three main questions are examined. First I show there were not just scientific and technical but also political, economical as well as military reasons to build a European rocket base. Second, I scrutinize the reasons to choose Northern Sweden as the location for the rocket base. As it turns out, the main reasons were the favourable location of Northern Sweden within the aurora oval zone, the proximity of the Kiruna Geophysical Observatory, and the possibility to use a large, although not quite uninhabited, area where the launched rockets could crash. Finally, I examine the difficulty of talking about boundaries of various kinds, such as temporal, spatial and functional. The essay also provides a discussion on possible ways to continue research on this topic.

  • 56.
    Bagir, Mohammad
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konstruktion av broms till motståndsvagn2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Baltic fitness, which is the project owner, is a company that invests in Swedish-made training equipment. This work has been about constructing a resistance brake for a weight-bearing resistance sled, consisting of a chassis on wheels and four handles. Resistance sleds are often used for training purposes where the practitioner pulls or pushes the handles. In order for the exercise to have maximum effect the carriage must have some type of braking function that gives more resistance to the work and makes the work heavier.

     

    A preliminary study initiated the project to investigate various brake types and resistors used in vehicles and training equipment. Concepts for the brake function were designed with regard to the carriage construction and the requirements set by the project owner. Calculation have been made to ensure that the braking function creates sufficient resistance.

     

    The final result was two concept proposals, a magnetic resistance brake that acts like an electromagnetic retarder in heavy vehicles, without mechanical friction. The second concept is an electric resistance brake where an electric motor acts as a generator and a high load resistor loads the motor shaft.

  • 57.
    Baigmohammadi, Mohammadreza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. Combustion and Turbulence Research Laboratory (CTL), Department of Aerospace Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Ave, Tehran, Iran.
    Tabejamaat, Sadegh
    Experimental study on the effect of external thermal pattern on the dynamics of methane-oxygen and methane-oxygen-carbon dioxide premixed flames in non-adiabatic meso-scale reactors2019In: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 137, p. 242-252Article in journal (Refereed)
    Abstract [en]

    In the current study, the effect of external thermal pattern on the dynamics and characteristics of methane oxygen and methane-oxygen-carbon dioxide premixed flames in non-adiabatic meso-scale cylindrical reactors is investigated experimentally. In this regard, two different external thermal patterns were imposed on the outer surface of the reactors. The results showed that imposing method/direction and also temperature level of the external thermal pattern have impressive effect on flame dynamics and chemiluminescence in the non-adiabatic meso-scale reactors. Also, it was shown that increasing the temperature level of the external thermal pattern could significantly extend the flame stability and its presence range in the meso-scale reactors, especially for the vitiated mixtures (methane-oxygen-carbon dioxide). Moreover, the results demonstrated that decreasing the inner diameter of a meso-scale reactor, which was subjected to an external thermal pattern, could increase the flame controllability and its presence range in the non-adiabatic meso-scale reactors.

  • 58.
    Baigmohammadi, Mohammadreza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. Combustion and Turbulence Research Laboratory (CTL), Department of Aerospace Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Ave., Tehran, 15875-4413, Iran.
    Tabejamaat, Sadegh
    Faghani-Lamraski, Morteza
    Experimental study on the effects of mixture flow rate, equivalence ratio, oxygen enhancement, and geometrical parameters on propane air premixed flame dynamics in non-adiabatic meso-scale reactors2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 121, p. 657-675Article in journal (Refereed)
    Abstract [en]

    In the present study, the effects of reactive mixture flow rate, adding oxygen to propane-air mixture, geometrical parameters, and equivalence ratio on propane-air/oxygen premixed flame dynamics in non adiabatic meso-scale reactors were experimentally investigated. During the experiments, seven flame regimes of blow-off, blow-out, asymmetric stationary, stationary-repetitive extinction and re-ignition (RERI), forced/self-RERI, RERI-flash-back, and flash-back were observed. The results showed that increasing the reactive mixture flow rate could generally promote variety of the flame regimes and also improve flame stability in the non-adiabatic meso-scale reactors, especially in 40% and 80% oxygen enhanced cases. Also, the results demonstrated that increasing the reactor inner diameter and equivalence ratio generally extended propane-air- oxygen flame stability and its presence range in the non adiabatic meso-scale reactors. Moreover, it was shown that increasing the reactor length and also increasing the added oxygen to propane-air mixture more than 40% promoted flame instability and consequently restricted propane-air-oxygen flame presence range in the non-adiabatic meso-scale reactors. Also, it was shown that variations in the mixture flow rate, the reactor length and inner diameter, equivalence ratio, and oxygen concentration in propane-air mixture could significantly influence the flame average propagation speed, acoustic, and chemiluminescence in the non-adiabatic meso-scale reactors.

  • 59.
    Baigmohammadi, Mohammadreza
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Tabejamaat, Sadegh
    Javanbakht, Zeinab
    Numerical Study of Methane-Oxygen Premixed Flame Characteristics in Non-adiabatic Cylindrical Meso-Scale Reactors with the Backward-Facing Step2019In: Iranian Journal of Science and Technology, Transactions of Mechanical Engineering, ISSN 2228-6187, Vol. 43, p. 117-140Article in journal (Refereed)
    Abstract [en]

    In the present study, the effects of reactor diameter, inlet velocity, velocity profile, equivalence ratio (Phi, Ф), and outer wall convective and radiative heat transfer coefficients on flame characteristics in cylindrical non-adiabatic meso-scale reactors with the backward-facing step were investigated numerically. The results showed that these parameters could strongly affect the mole fraction of radical species within the flame zone. Also, it was shown that as compared to the reactor with 3 mm inner diameter, increasing the inlet velocity in the reactor with 5 mm inner diameter may lead to the opposite effect on the flame location. In addition, it was observed that the velocity profile could sensibly affect the flame location, temperature, and the species mole fractions in the meso-scale reactors. Moreover, it was demonstrated that the effect of equivalence ratio on the flame characteristics was more crucial for the reactors with smaller diameters. Furthermore, it was maintained that the outer wall convective and radiative heat transfer coefficients could cause the flame instability in the meso-scale reactors because of decreasing the mole fraction of important species such as O, H, and OH in the vicinity of the reactor inner wall.

  • 60.
    Bassem, Mohammad
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förbränning av träpellets och pelleterad halm i en 40 kW rosterreaktor2012Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [sv]

    The project focus on combustion of softwood pellets and pellets in a 40 kW grate fire reactor at TEC-Lab. Dept Applied Physics and Electronics at Umeå University. Experiments were performed at four primary airs to fuel ratios (0.7 to 1.3), where aspects such as temperature profile, levels of gases (CO and NO), sintering-/-slagging and unburned fraction of the ashes were studied. Four different fuel loads were used for wood pellets (10, 20 and 30 kW) and one fuel load for straw (10 kW). Combustion of straw proved very difficult to ignite, and also led to other combustion-related technical problem such as slag formation due to the relatively low melting temperature-/-slag temperature of the straw. Causing undesired silicate melt on the grate. The straw was only possible to use low load operation (10 kW) because it was difficult to manage. The temperature of the bed varied between the studied cases with varying fuel loads and air to fuel ratios.

  • 61.
    Bejarano, Maria Dolores
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sordo-Ward, Alvaro
    Alonso, Carlos
    Nilsson, Christer
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Characterizing effects of hydropower plants on sub-daily flow regimes2017In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 550, p. 186-200Article in journal (Refereed)
    Abstract [en]

    A characterization of short-term changes in river flow is essential for understanding the ecological effects of hydropower plants, which operate by turning the turbines on or off to generate electricity following variations in the market demand (i.e., hydropeaking). The goal of our study was to develop an approach for characterizing the effects of hydropower plant operations on within-day flow regimes across multiple dams and rivers. For this aim we first defined ecologically meaningful metrics that provide a full representation of the flow regime at short time scales from free-flowing rivers and rivers exposed to hydropeaking. We then defined metrics that enable quantification of the deviation of the altered short-term flow regime variables from those of the unaltered state. The approach was successfully tested in two rivers in northern Sweden, one free-flowing and another regulated by cascades of hydropower plants, which were additionally classified based on their impact on short-term flows in sites of similar management. The largest differences between study sites corresponded to metrics describing sub-daily flow magnitudes such as amplitude (i.e., difference between the highest and the lowest hourly flows) and rates (i.e., rise and fall rates of hourly flows). They were closely followed by frequency-related metrics accounting for the numbers of within-day hourly flow patterns (i.e., rises, falls and periods of stability of hourly flows). In comparison, between-site differences for the duration-related metrics were smallest. In general, hydropeaking resulted in higher within-day flow amplitudes and rates and more but shorter periods of a similar hourly flow patterns per day. The impacted flow feature and the characteristics of the impact (i.e., intensity and whether the impact increases or decreases whatever is being described by the metric) varied with season. Our approach is useful for catchment management planning, defining environmental flow targets, prioritizing river restoration or dam reoperation efforts and contributing information for relicensing hydropower dams. 

  • 62.
    Bengtsson, Rikard
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konceptdesign av redskapstilt anpassad för frontlastare: Utformning och tillverkning av prototyp för Ålö AB2016Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport beskriver utformandet av en redskapstilt konstruerad för frontlastare till jordbrukstraktorer. Redskapstilten är ett tillbehör vars syfte är att skeva redskapet i olika vinklar som är användbart vid markberedningar, pallmanövrering och liknande arbeten. Projektet genomförs på uppdrag av Ålö AB i Umeå som tillverkar både frontlastare och tillbehör till jordbrukstraktorer. Det långsiktiga målet för projektet är att ta fram en prototyp av en redskapstilt, samt att undersöka om det finns någon marknad för detta tillbehör till Ålös frontlastare. På grund av tidsbrist behandlar denna rapport endast framtagandet av konceptidén.Vid projektstarten genomfördes en marknadsundersökning för att ta reda på om redskapstilt för frontlastare, anpassad för jordbrukstraktorer, redan fanns tillgängligt på marknaden. Redskapstiltar är vanliga tillbehör för hjullastare och förekommer i tre olika koncept. De olika alternativen skiljer sig avseende på tiltfunktionens montage. Tilten kan vara monterad direkt på ett redskap, exempelvis fäst på en skopa med tiltfunktion. Den kan även byggas som en adapter, som enkelt kan monteras av och på lastarens redskapsfäste. Alternativt kan tilten byggas som ett helt nytt redskapsfäste med skevfunktion, som ersätter det befintliga redskapsfästet på frontlastaren.Med konceptstudien som grund listades de olika lösningsförslagens för- och nackdelar mot varandra. Det bästa alternativet visade sig vara ett redskapsfäste med skevfunktion, vilket kom att utgöra fokus för resten av projektet. Många olika faktorer vägdes in gällande redskapstiltens konstruktion under utformningen av lösningsförslaget. Krav som ställdes på konstruktionen var att infästningen till lastaren skulle stämma överens med befintligt redskapsfäste och anpassas efter Euro-typ. Dessutom skulle konstruktionen byggas med artiklar ur Ålös sortiment i största möjliga utsträckning, för att hålla tillverkningskostnaderna nere. Konstruktionen designades i CAD-programmet Solid Edge.Resultatet av projektet är en redskapstilt som i teorin uppfyller de för konstruktionen fastställda kraven. Konceptidén utgörs av en kompakt konstruktion, delvis bestående av komponenter från Ålös sortiment, som klarar simulerade kollisonstester med Ålös frontlastare. Fördjupade hållfasthetsberäkningar och ritningsunderlag kvarstår att genomföra innan en eventuell prototyptillverkning är aktuell.

  • 63.
    Bergdal, Tobias
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Teleskopisk redskapsbärare för hjullastare: Utveckling av en idé till en ny typ av hjullastarredskap2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Hjullastaren är en vanligt förekommande maskin på byggarbetsplatser. Där sköter den främst materialhantering och allmän logistik. De flesta husbyggen görs idag i fler våningar än enbart markplan och här begränsas hjullastarens konkurrenskraft av sin utformning då den inte klarar att leverera material till särskilt höga höjder. Detta arbete syftar till att utveckla en idé kring en ny typ av redskap vilket skulle ge hjullastaren möjlighet att utöka sin räckvidd vid materialhantering och därigenom öka sin konkurrenskraft jämte andra maskintyper.

    Arbetet har begränsats till utveckling av idén kring den nya redskapstypen varför frågor rörande lagkrav, säkerhet och dylikt har utelämnats.

    I arbetet har flertalet studiebesök genomförts hos olika återförsäljare, yrkesverksamma inom åkeri- och entreprenadbranschen och på byggarbetsplatser för att samla information om problemet och hämta inspiration till möjliga tekniska lösningar för den nya redskapstypen. En sammanställning av denna information har lett fram till den kravspecifikation som senare legat till grund för konstruktionen av redskapskonceptet. Hjullastarredskapet ska bland annat klara att tillsammans med hjullastaren ställa av material på ett par bockar på tredje våningens balkong (7,7 meter) samtidigt som den ska klara materialhantering under marknivå (-0,5 meter). Det sistnämnda eftersom redskapet ska erhållas användbart i nedförslutande mark. Den teleskopiska redskapsbäraren ska ha ett redskapsfäste med full funktionalitet för att kunna hantera vanligt förekommande hjullastarredskap både horisontellt och vertikalt mot marken. Redskapsbäraren ska dimensioneras för att klara en last av 2000kg. Som namnet antyder ska produkten även ha en teleskopisk funktion som ger ett smidigt och lätthanterligt redskap med god räckvidd.

     Utifrån kravspecifikationen och de önskade funktionerna på konceptet har skisser ritats. Dessa har legat som grund för de hållfasthetsberäkningar som gjorts och det efterföljande konstruktionsarbetet i Catia.

    Resultatet av arbetet har lett fram till ett koncept där den teleskopiska funktionen utgörs av två fyrkantsprofiler som ligger omlott om varandra. Dessa fästs in i en ”ram” tillverkad av fyrkantsprofiler. Längst ut på den rörliga teleskopbalken sitter ett Volvo L50 redskapsfäste för tillkoppling av hjullastarredskap.

    Konceptet uppfyller kraven ställda i kravspecifikationen samt de tippvinklar som behövs för att kunna hantera material på ett säkert sätt både i marknivå och uppe på höjder motsvarande tredje våningen.

    Avslutningsvis diskuteras designförändringar som skulle kunna bli aktuella om konceptet vidareutvecklas, t.ex. hur vikten och därigenom prestandan kan optimeras för redskapet genom att bland annat ta reda på aktuella spänningskoncentrationer genom FEM-analys och byte till ett klenare men lättare redskapsfäste.

  • 64.
    Bergenström, Rikard
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Höghöjdsanpassning av BvS10: Konceptstudie för optimering av överladdningssystem2014Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    This report relate a concept study that consider a number of different proposals to improve the overcharging system in BAE Systems Hägglunds tracked vehicle series BvS10, to maintain sealevel power at extreme altitude.

    At high altitude the power losses beacuase of the air density that decreases, which results in less fuel can be burned. The decreasing of air density also gives rise to fatigue failure of the turbocharger unless power is reduced.

    The proposals shall be as required by BAE Systems Hägglunds economically sustainable and defensible from a packing perspective. That means the selected solution must have a reasonable price tag and at the same time a minimal impact on adjacent components.

    The basis for this thesis is based on benchmarking of both the auto industry as the flight industry, to find inspiration and tips for improvement.

    Some of the concepts have after gathering facts and calculations been excluded while other solutions has been considered as workable and thus interesting for BAE Systems Hägglunds.

    Initially the current turbochargingsystem was analyzed in order to determine the starting point and thus be able to fix the current problems surrounding high altitude driving. Since then, various concepts has been studied in form of single turbocharger, twostage turbocharging, turbocharger-supercharger compound, material exchange of impeller and engine optimization.

    The solution that is concidered to works especially well for BAE Systems Hägglunds tracked vehicle series, is to complement the current turbocharging setup with a centrifugal supercharger. 

  • 65.
    Berggren, Martin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Bernland, Anders
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Noreland, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Acoustic boundary layers as boundary conditions2018In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 371, p. 633-650Article in journal (Refereed)
    Abstract [en]

    The linearized, compressible Navier-Stokes equations can be used to model acoustic wave propagation in the presence of viscous and thermal boundary layers. However, acoustic boundary layers are notorious for invoking prohibitively high resolution requirements on numerical solutions of the equations. We derive and present a strategy for how viscous and thermal boundary-layer effects can be represented as a boundary condition on the standard Helmholtz equation for the acoustic pressure. This boundary condition constitutes an O (delta) perturbation, where delta is the boundary-layer thickness, of the vanishing Neumann condition for the acoustic pressure associated with a lossless sound-hard wall. The approximate model is valid when the wavelength and the minimum radius of curvature of the wall is much larger than the boundary layer thickness. In the special case of sound propagation in a cylindrical duct, the model collapses to the classical Kirchhoff solution. We assess the model in the case of sound propagation through a compression driver, a kind of transducer that is commonly used to feed horn loudspeakers. Due to the presence of shallow chambers and thin slits in the device, it is crucial to include modeling of visco-thermal losses in the acoustic analysis. The transmitted power spectrum through the device calculated numerically using our model agrees well with computations using a hybrid model, where the full linearized, compressible Navier-Stokes equations are solved in the narrow regions of the device and the inviscid Helmholtz equations elsewhere. However, our model needs about two orders of magnitude less memory and computational time than the more complete model. 

  • 66.
    Berggren, Martin
    et al.
    Department of Information Technology, Uppsala University.
    Bängtsson, Erik
    Department of Information Technology, Uppsala University.
    Noreland, Daniel
    Department of Information Technology, Uppsala University.
    Multifrequency shape optimization of an acoustic horn2003In: Computational Fluid and Solid Mechanics 2003 / [ed] K. J. Bathe, 2003, p. 2204-2207Conference paper (Refereed)
  • 67.
    Berggren, Martin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Lacis, Ugis
    Lindström, Fredrik
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Sound vibration damping optimization with application to the design of speakerphone casings2013In: : Paper id 5569, 2013Conference paper (Refereed)
    Abstract [en]

    We optimize the thickness distribution in a 1D beam model of an elastic plate, subject to forced vibration at one of its ends, in order to minimize the structural vibration in a given area of the plate. The optimization is carried out both in broadband and band-pass cases. Geometric constraints, weight constraints, and constraints on the static compliance are imposed in the optimization. A broadband optimization over 50 frequencies, evenly distributed in the 300–3400 Hz range, reduces the vibration by around 5–10 dB on average throughout the frequency range. When targeting only the higher end of the above frequency range, it is possible to achieve more dramatic results. Vibration reductions of 20 dB and more can be achieved in the 2300–2800 Hz region. In the latter case, the results suggest that a band-gap phenomenon occurs, similarly as for phononic band gap materials. To validate the results, the best-performing optimal shape for the clamped case was imported into a 3D computational structural model, and the resulting forced vibration response agreed well with the the beam-model computations. These results were first announced in a technical report by Lacis et al. [5].

  • 68.
    Berggren, Thor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av värmesystem, förslag på effektiviseringar för att värma vatten/ballast för   modulära betongstationer2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this thesis I examine the potential to recover some of the heat used to warm up ballast when the material is stored in ballast tanks, at an industrial sized concrete facility at outdoor temperatures below +5 °C. Three different cases with different heating applications are covered. All calculations has been made using 0 °C as outdoor temperature, results with varying outdoor temperature is shown in graphs at the end of the results chapter.

    Case 1, where the ballast is heated with humidified flue gas has a calculated estimated output of 506 kW, of these 506 kW, 67.5 kW can be recycled, which means that the theoretical percentage of recyclable power is 13.4%. Furthermore, the calculations show that the inlet temperature drops from 300 °C to 162 °C just above the ballast. The time for heating the material is in this case 5 minutes.

    Case 2, where the ballast is heated with dry hot air at a calculated estimated output of 10 kW, of these 10 kW, 7.6 kW can be recycled, which means that the theoretical percentage of recyclable power is 76.3%. Furthermore, the calculations show that the inlet temperature drops from 100 °C to 78 °C just above the ballast. The time for heating the material is in this case 16 hours.

    Case 3, where the ballast is heated with humidified air has a calculated estimated output of 85.3 kW, where all power is used to heat the ballast. The case is shown to work with a deficit of energy which means the ballast could absorb a lot more power than is actually available. Therefore, the percentage of recoverable energy is 0 %, and consequently the inlet temperature drops from 100 °C to 0 °C

  • 69.
    Berglund, Anders
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Application of an alternative frequency response technique to the durability assessment of engine components2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Engine components are exposed to vibrations which may lead to fatigue damage. Accurate dynamic simulations are necessary especially during the development process, in order to find a satisfactory component.

    Currently Scania uses a standard method for dynamic calculations that is based on a frequency response approach. A measured or calculated excitation yields a certain response through the transfer function of the system. The transfer function is obtained through an eigenfrequency calculation and an experience-based estimate of the modal damping. An obvious drawback of this method is that the estimated modal damping strongly affects the calculated response of the system.

    In this thesis, the method outlined above is compared to an alternative, so-called, inverse method in which the excitation of the system is calculated using a measured response. The advantage is that the modal damping does not affect the result directly since the excitation has been adjusted according to the response. As a demonstration object a charge air pipe and its bracket are used. Acceleration response data is collected from an engine vibration measurement.

    The calculated safety factor of the demonstration object is reasonable for both the standard method and the inverse method. An estimate of the quality of the model is obtained for the inverse method through statistical measures, which is not the case for the standard method. The excitation for the inverse method is adjusted to the estimated modal damping which is a major advantage since damping is notoriously difficult to quantify in engineering practice. The inverse method has proven to be a useful simulation method for calculations when a prototype of the engine component of interest already exists.

  • 70.
    Berglund, Beatrice
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analys av dimensionerande temperaturer från värmeåtervinningsbatteri till frånluftsvärmepump2012Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There are a large number of houses that have no heat recovery in the ventilation systems at present. There is an option to install heat recovery batteries to the exhaust air ducts that is connected to heat pumps in order to meet energy reduction targets for 2020 and 2050.

    The purpose of this project has been to investigate how energy consumption and annual cost depends on the design temperatures of the heat recovery battery. The parameters that have been investigated are normal variations of:

    -          Exhaust air temperature

    -          The moisture content in the exhaust air

    -          Exhaust air flow over battery

    -          Liquid flow over battery

    The overall coefficient of performance (COP) of the system has been studied for heat pumps with or without variable speed. The efficiency has also been investigated when solar panels are connected to the system.

    Two batteries have been simulated, a traditional battery from Luvata and one needle pipe battery from Retermia. The two heat pumps which have been investigated are one heat pump from IVT and one industrial heat pump with speed control from Kylma.

    Calculations and simulations have been made in the program Coils and Microsoft Excel.

    The cases that have been investigated are:Case 1: Luvata battery connected to Kylma heat pumpCase 2: Retermia battery connected to Kylma heat pumpCase 3: Luvata battery connected to IVT heat pump

    A comparison of annual costs for heating water with a heat pump system or with district heating was made.

    The results from the calculations for the batteries show that the Luvata battery can absorb more heat than the Retermia battery in most cases, because of its higher temperature efficiency, about 81 % compared to 71 %.

    The COP for Kylma were shown between 3.9 and 4.1 and for IVT between 2.6 and 2.8. Case 1 and case 2 will have the best options with a total COP of about 3.8 for every parameter variation, while case 3 gives a total COP of about 2.5 for every parameter variation, when the total COP of the system were calculated.

    In the calculations of which case that is most profitable the answer is case 2, with an annual cost divided by the produced thermal energy about 390 kr/MWh compared to the case where a district heating exchanger were installed about 640 kr/MWh.

    The total COP and the annual costs can be concluded that case 2, when Retermia battery is connected to a Kylma heat pump, is the best option based on the calculations that has been performed.

  • 71.
    Bergman, Jonathan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Technical Solutions in Dimensioning an Industrial Torrefaction Facility2017Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    The full text will be freely available from 2022-05-31 15:55
  • 72. Bergström, Dan
    et al.
    Israelsson, Samuel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Dahlqvist, Sten-Axel
    Gref, Rolf
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Wästerlund, Iwan
    Effects of raw material particle size distribution on the characteristics of Scots pine sawdust fuel pellets2008In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 89, no 12, p. 1324-1329Article in journal (Refereed)
    Abstract [en]

    In order to study the influence of raw material particle size distribution on the pelletizing process and the physical and thermomechanical characteristics of typical fuel pellets, saw dust of Scots pine was used as raw material for producing pellets in a semi industrial scaled mill (similar to 300 kg h(-1)). The raw materials were screened to a narrow particle size distribution and mixed into four different batches and then pelletized under controlled conditions. Physical pellet characteristics like compression strength, densities, moisture content, moisture absorption and abrasion resistance were determined. In addition, the thermochemical characteristics, i.e. drying and initial pyrolysis, flaming pyrolysis, char combustion and char yield were determined at different experimental conditions by using a laboratory-scaled furnace. The results indicate that the particle size distribution had some effect on current consumption and compression strength but no evident effect on single pellet and bulk density, moisture content, moisture absorption during storage and abrasion resistance. Differences in average total conversion time determined for pellet batches tested under the same combustion conditions was less than 5% and not significant. The results are of practical importance suggesting that grinding of saw dust particle sizes below 8 mm is probably needless when producing softwood pellets. Thus it seem that less energy could be used if only over sized particles are grinded before pelletizing.

  • 73. Bergström, Dan
    et al.
    Israelsson, Samuel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Dahlqvist, Sten-Axel
    Gref, Rolf
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Wästerlund, Iwan
    Effects of raw material particle size distribution on the characteristics of Scots pine sawdust fuel pellets2008In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 89, no 12, p. 1324-1329Article in journal (Refereed)
    Abstract [en]

    In order to study the influence of raw material particle size distribution on the pelletizing process and the physical and thermomechanical characteristics of typical fuel pellets, saw dust of Scots pine was used as raw material for producing pellets in a semi industrial scaled mill (similar to 300 kg h(-1)). The raw materials were screened to a narrow particle size distribution and mixed into four different batches and then pelletized under controlled conditions. Physical pellet characteristics like compression strength, densities, moisture content, moisture absorption and abrasion resistance were determined. In addition, the thermochemical characteristics, i.e. drying and initial pyrolysis, flaming pyrolysis, char combustion and char yield were determined at different experimental conditions by using a laboratory-scaled furnace. The results indicate that the particle size distribution had some effect on current consumption and compression strength but no evident effect on single pellet and bulk density, moisture content, moisture absorption during storage and abrasion resistance. Differences in average total conversion time determined for pellet batches tested under the same combustion conditions was less than 5% and not significant. The results are of practical importance suggesting that grinding of saw dust particle sizes below 8 mm is probably needless when producing softwood pellets. Thus it seem that less energy could be used if only over sized particles are grinded before pelletizing.

  • 74.
    Bjarnhagen, Rikard
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Service Enhancer Tool: Design of a new Service Enhance Tool for Metso refiners2013Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Metso develops (among many other things) refiners. The refiner grinds the wood chips intopulp. The grinding is done by segments that are placed on a rotor inside the refiner hosing.In time this segments wear and needs to be replaced.When changing refiner segments or performing service to the refiner the rotor needs to berotated. To perform the rotating motion today the overhead crane is used. This procedure isboth impractical, dangerous and takes precious time from the overhead crane. Because ofthis Metso wanted to create a new way to rotate the rotor.The aim of this thesis is to create a tool or equipment which can be used to rotate therefiner rotor and can be installed as an upgrade on all Metso refiner models.The proposed design is driven with a 1.1 kW electrical motor and a gearbox with a gear ratioof approximately 1:217. The torque is transferred from the outgoing gearbox shaft to therefiner shaft with the help of gearwheels. To connect the gearbox gearwheel with the refinershaft gearwheel, the gear motor has to be moveable in a radial direction. This is done by themeans of two shafts that glides in four bushings. On the gearbox shaft a gearwheel with 120mm of face width is mounted. The large face width is used to take up the axial movement ofthe refiner shaft.The proposed concept fulfills all of the demands set in the pilot study. The design is goodbecause of the low cost and straight forward design that is easy to build and simple to use.The disadvantage is that the equipment is a bit large and heavy, but as stationary equipmentthis should not be a problem.

  • 75.
    Björk, Alexander
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Control of Multibody Machines using Rate Gyros and Optronics2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project deals with design and prototype testing of a reversing car trailer systemequipped with a rate gyro and optronics to locate a target and drive to it. Simulink isused for developing and implementing the control system, it was also used to remotelyoperate the vehicle with a Man-in-the-Loop input. Given a starting position the user cancontrol a servo holding a laser range finder and a laser pointer to find a suitable target,and then lock the vehicle on it to later make it autonomously approach it.

    The finished car trailer system can, when driving straight backwards, reach the destinationwithin the vicinity of 10 ± 7 cm from a starting position 3 m away. When reversingto a target with an angular offset the accuracy and precision is decreasing.

    Provided the short time frame for a project that covers both designing, building andtesting of the final product the robot was experimentally tested only a few times. Moretesting is necessary to show limitations in design and implementation.

    The combination of experimental results and simulations this project has resulted inshows a proof of concept for this type of autonomous vehicle, although further improvementsand tests are vital to improve performance and reliability.

  • 76.
    Björk, Alexander
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Control of Multibody Machines usingRate Gyros and Optronics2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project deals with design and prototype testing of a reversing car trailer systemequipped with a rate gyro and optronics to locate a target and drive to it. Simulink isused for developing and implementing the control system, it was also used to remotelyoperate the vehicle with a Man-in-the-Loop input. Given a starting position the user cancontrol a servo holding a laser range finder and a laser pointer to find a suitable target,and then lock the vehicle on it to later make it autonomously approach it.

    The finished car trailer system can, when driving straight backwards, reach the destinationwithin the vicinity of 10 ± 7 cm from a starting position 3 m away. When reversingto a target with an angular offset the accuracy and precision is decreasing.

    Provided the short time frame for a project that covers both designing, building andtesting of the final product the robot was experimentally tested only a few times. Moretesting is necessary to show limitations in design and implementation.

    The combination of experimental results and simulations this project has resulted inshows a proof of concept for this type of autonomous vehicle, although further improvementsand tests are vital to improve performance and reliability.

  • 77.
    Björklund, Lina
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utvärdering av byte till energieffektiv belysning i tryckeri2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The result of an energy survey at the printing company VK – Media showed that the energy use of the old lighting was a large part of the total energy use. The old lighting with high-pressure sodium luminaires and high-pressure sodium light sources was then replaced with a new energy-efficient lighting with two different LED luminaires in the packaging room at the printing company. An evaluation of the replacement of the luminaires should now be carried out. The evaluation of the lighting change is based on the reduction of energy use, differences of illuminance and changes in the working environment.

     

    The primary aim of the lighting replacement is to reduce the energy use and to improve the working environment. Simulations on the lighting with high-pressure sodium light sources and LED luminaires have been made in DIALux evo. In DIALux, calculations were made on illuminance and energy use. Momentary power measurements with a multimeter have been carried out on the lighting before and after the replacement. The measured power was then used to calculate the annual energy use for the luminaires. The illuminance were measured with a luxmeter in the packing room and the measured values was then used to calculate the average illuminance and the uniformity of the lighting, to see if they stand against the guideline values and compare them with the values from DIALux. The life cycle cost was calculated for the lighting with high pressure sodium light sources and for the lighting with LED luminaires. The payback time was also calculated for the new lighting with LED luminaires.

     

    The result of the calculations on the energy use showed that the annual energy use will be reduced by 70 per cent with the LED luminaires and the aim with a lighting replacement is to reduce the annual energy use by 50 percent. The average illuminance of the new LED lighting is about 680 lx meets the requirement for the average illuminance of 300 lx that applies to the packing room according to the standard SS-EN 12464-1: 2011. The life cycle cost of the old lighting and the new LED lighting was estimated at approximately 990,000 SEK and 330,000 SEK, respectively. The discounted payback time for the LED lighting was estimated at 1.7 years. Regarding the working environment, the LED lighting has been mounted at a luminaire height that is too low and will be raised to achieve a more comfortable working environment.

     

    Investing in a new energy-efficient lighting means a large reduction in annual energy use, while the investment has a relatively short repayment period. There are many advantages to replacing the old lighting such as an improved work environment and reduced costs for the company. Hopefully, more industries will replace their old lighting for energy-efficient lighting as they account for a large part of the total electricity use when it comes to lighting in Sweden.

  • 78.
    Björklund, Viktor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimering av plocksignal2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Examensarbetet skrivs på Scania CV AB i Södertälje hos gruppen MSLT som arbetar inom logistikutveckling hos alla monteringsavdelningar hos chassimonteringen. Examensarbetet fokuserar på en av dessa monteringsavdelningar med benämningen FFU – Fit For Use och dess logistikgrupp MSLFL.

     

    Chassimonteringen är uppdelad i 14 antal områden längs med monteringslinan där varje område utför olika typer av monteringar och arbeten. I det stora hela fungerar det så att sidobalkar levereras i ena änden av fabriken och i den andra änden kommer en färdig lastbil ut. Under denna resa levereras och monteras det som en standardlastbil behöver.

    FFUs del i denna montering kommer in när en kund har speciella önskemål till sin lastbil, som då alltså frångår det som ingår i en standardlastbil. De olika monteringsarbetena som krävs vid de olika specifika önskemålen kan ej utföras på den ordinarie monteringslinan och utförs därför hos FFU. På FFU finns logistikavdelningen MSLFL vars uppgift är att plocka ihop och leverera materialet till monteringen hos FFU.

     

    Det problem som uppstår idag är att planeringen och tidpunkten för plocksignalen till logistikavdelningen MSLFL på FFU ej är optimal. Detta leder till att artiklar plockas från lager för tidigt och blir sen stående i väntan på montering. Detta ger i sin tur platsbrist hos MSLFL vid leveransytan till monteringen hos FFU. Materialet som behövs för monteringen på FFU plockas i ett för tidigt skede i förhållande till själva monteringen. Det är denna problematik som examensarbetet behandlat och undersökt.

     

    Examensarbetet är uppdelat i tre delar. Från start utförs en två veckor lång praktik hos logistikavdelningar på chassimonteringen. Sedan påbörja en empirisk undersökning som består av intervjuer med anställda på de påverkade avdelningarna, där syftet att hitta någon eventuell lösning. Den empiriska undersökningen utförs under fem veckor. Resterande tid läggs på att skriva rapport och planera redovisning som sker både hos Scania och vid Umeå universitet.

     

    Den empiriska undersökningen har lett fram till tre plausibla lösningar där förslag tre, att sätta ett eget Topp-CU till FFU anses som det bästa och mest relevanta då det skulle ändra förutsättningarna för planeringen hos FFU och MSLFL. Alla lösningsförslagen i denna rapport kräver dock vidare undersökningar i framtida projekt för optimering och eventuellt genomförande.

  • 79.
    Blomdahl, Pontus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Utmattningsprovning av kamringar: Framtagning av testutrustning för utmattningsprovning av kamringar2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Bosch Rexroth in Mellansel develops and fabricates Hägglunds hydraulic motors among other things. One important component of the motor is the cam ring, which commonly affects the life span of the motor. The aim is to create the basis of a testing equipment where a loose cam ring can be tested. Previously, a complete motor has been used in order to test the fatigue resistance of the cam ring. In order to load the cam ring similar to the real case. FEM-analysis was performed to investigate how the cam ring is affected during loading and how the rig should be built for the strains to be similar to the real case. The result of this simulation was compiled in a Haighdiagram in order to get an indication of the magnitude of the stresses. The solution is a testing equipment which consist of a cylinder block which usually is in the motor. The cylinder block is bolted onto a bottom plate where the cam ring has a given position. The cam ring is fixated using a sloted spring pin and a dowel pin that keeps the cam ring in position and prevents potential torque. All pistons should be pressurised by pulsation at the same time using the same pressure, thus, the torque is expected to be zero. One of the holes which is holding the cam ring is oval, this is to allow deformation of the cam ring. The result of this work is a basic plan for the components included which affects the mechanical function of the testing equipment. A limitation of this work has been that the residual stresses in the clearance holes is unknown. These residual stresses have a great importance for fatigue resistance of the cam rings. As a consequence of this, it has been difficult to estimate which working pressure the test rig has to use in order to achieve the desired life span. Experimental testing when using the rig will indicate this. Task monotoring  The testing equipment will generate 1-10 million loading cycles before failure of the cam ring occurs. Will be achieved through experimental testing  Testing time should be reasonable, result would preferably be achieved within 2-4 weeks. Will be achieved through experimental testing  The testing equipment should be customised for a CA 50-50 cam ring. (CA 50 motor series strongest motor 50 Nm/bar) Achieved  Testing equipment should be usable with the current laboratory equipment of Bosh Rexroths (420 bars maximum preassure). Probably achieved  The crack needs to be detected in an appropriate way, to stop the testing. Achieved  The testing equipment needs to be able to be manufactured by using the developed blueprints. Achieved

  • 80.
    Blomqvist, Benjamin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rönntoft, Britta
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jet flow simulations of Baihetan hydropower station’s discharge surface spillways2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This project was performed in order to determine if numerical simulations can be used to predict the spreading of a water jet that exits the discharge surface spillways of Baihetan hydropower station. If the spreading ranges can be predicted correctly using numerical simulations, the pressure distribution in the plunge pool downstream the dam can be determined. By being able to determine the pressure distribution, the spillways’ design can then be modified in order to optimize the pressure distribution and thereby minimize the damage on the plunge pool’s river bed. If the spreading ranges can be predicted correctly using numerical simulations it means that numerical simulations can be used as a tool to design future hydropower stations’ discharge surface spillways as a substitute to scale models which are commonly used to optimize the spillway design today.

    A simulation model of Baihetan Hydropower station’s discharge surface spillways was constructed. The model was constructed as two separate parts using the pre-processing software Gambit and then imported to the computational fluid dynamics software Fluent for numerical simulation of the water flow. The numerical simulations were performed with a transient flow, the k-ε turbulence model and the Volume of Fluid multiphase model. The models were simulated with a water level in the dam corresponding to when a massive flood has occurred which happens approximately once every hundred years. The results from the numerical simulation were then analyzed with the post-processing software Tecplot 360. Results in form of water spreading ranges when the jet stream hits the plunge pool were obtained from the numerical simulation and compared to data from an earlier performed experimental study where a scale model was used. The water spreading ranges were measured using a water volume fraction of 0-5 percent. The comparison was done to be able to determine if the results from the numerical simulations were accurate enough so that numerical simulations could be used as a substitute to expensive scale models when designing hydropower stations’ discharge surface spillways. A sensitivity analysis was performed where different mesh sizes were used and the Fluent setting double precision mode.

    The numerical results were acceptable when checking for convergence, meaning that the equations involved in the simulations were solved properly. The relative difference in water spreading range in the direction of the flow for the Medium mesh size was below 20 percent and thereby considered acceptable while the relative difference in water spreading range perpendicular to the flow was 60 percent for the Medium mesh size and thereby far from acceptable. Possible reasons for these deviations from the experimental results are the approximated uniform velocity profile at the inlet of the spillway and the used k-ε turbulence model. Considering the results obtained in this project, without more detailed study, the numerical simulations using k-ε turbulence model are not advised as a substitute for the experimental methods to determine water flow out of the discharge spill ways of hydropower plants. With more information about the conditions at the inlet and the use of a different turbulence model more accurate results may be obtained. 

  • 81.
    Bodin, Kenneth
    et al.
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Lacoursière, Claude
    Umeå University, Faculty of Science and Technology, High Performance Computing Center North (HPC2N).
    Nilsson, Martin
    Servin, Martin
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Constraint based particle fluids on GPGPU2011Conference paper (Other academic)
    Abstract [en]

    We present a fluid simulation method adapted for stream parallelism on general purpose graphics processingunits (GPGPU). In this method the equations of Navier and Stokes are discretized using particles and kernelfunctions as in Smoothed Particle Hydrodynamics (SPH), but rather than using penalty methods or solving for a divergence free velocity field, incompressibility is enforced using holonomic kinematic constraints [1]. We useone constraint for each smoothed particle stating that the local density should be kept constant. Other constraintsare used for boundary conditions and multiphysics coupling. We also present a viscosity model in which theshear rate at each pseudo particle is constrained to satisfy a given constitutive law. The computation of theconstraint forces, namely, the pressure and the stresses, requires the solution system of linear equations whichhave a sparse, saddle point structure. These are solved using the Uzawa method of preconditioned conjugate gradients (CG) applied directly to the symmetric indefinite matrix. The overall simulation method has its rootsin a discrete variational principle and the SPOOK time stepping scheme for constrained mechanical systems [2].The SPOOK method is second order accurate on the positions and constraints violations, and is stable at largetime-steps, thus often allowing several orders of magnitude larger timesteps in our method compared to intraditional SPH methods. The numerical implementation on GPGPU that is the main result of this paper consistsof the following components: particle neighbour searches based on spatial decomposition; summation of kernel densities; construction of Jacobians representing the constraints on the density, boundary conditions, viscosityand multiphysics couplings; a Uzawa CG solver for the system of linear equations; and finally, discrete timestepping of velocities and positions. The CG solver is particularly suitable for stream computing since it is basedon matrix-vector multiplications. The sparse system data is stored in a compressed matrix format and the algorithms operating on this data on GPGPU are implemented in CUDA and OpenCL. Our simulation resultsinclude performance measurements, and validation of the method for benchmark problems. We achieve up totwo orders of magnitude speed-up from the GPGPU over traditional processors and together with the increased timestep efficiency of our method we arrive at interactive performance for systems with up to two million fluidparticles representing an incompressible fluid.

  • 82.
    Boman, Emil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Korrosion i avfallsförbränningspannor: - med en fördjupad studie av korrosion på överhettare2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Inspecta AB bedriver besiktning som en av deras huvudsysslor och besiktar värmekraftverket på Dåvamyran. Besiktning av pannan sker årligen. Detta är ett krav från arbetsmiljöverket genom AFS 2005:3 ”Besiktning av trycksatta anordningar”. Pannan gås igenom med avseende på säkerhet och kan om den inte anses uppfylla de ställda krav bli underkänd för drift. I besiktningen ingår besiktning av överhettartuberna och man har noterat att tuberna i överhettar 2 har börjat korrodera med en ökad hastighet.

    Anledningen till varför korrosionshastigheten ökat har inte kunnat fastställas, men en av anledningarna kan vara att sopsorteringen i samhället ökat. Problemen som uppstått kan man härleda till bränslet. Avfall är ett väldigt heterogent bränsle, vilket innebär att värmevärdet och sammansättningen varierar väldigt mycket. Detta leder till problem som orsakar kostsamma planerade och oplanerade stopp. För att minska problemen som uppstår kan man vidta åtgärder som att tillsätta additiv och byta tubmaterialet.

    Den korrosion som verifierades med hjälp av SEM/EDS-analysen var högtemperaturkorrosion i form av klorinducerad korrosion, detta ska dock inte ses som ett entydigt svar då endast en tub, som suttit på kanten av överhettaren blev analyserad. Den materialanalys som gjordes visade att materialstrukturen varit opåverkad.

    Umeå energi hade vidtagit tre åtgärder, vilka var att: skydda tubernas böjar med ett keramiskt material, sänka ångtemperaturen och byte av tubmaterial. Skyddet på tuberna visade sig inte fungerar då de slagits sönder av sotningen. Sänkningen av ångtemperaturen blev installerad 2011 och man hittade klorinducerade korrosion 2012 vilket leder till slutsatsen att den inte stoppat denna typ av korrosion. Materialet som Umeå energi hade valt till tuberna var Inconel 625 påsvetsad på ett låglegerat stål. Materialet har visat goda egenskaper i kloridrika miljöer och kommer högst sannolikt ge ett bra resultat, men till en initialt hög kostnad. En alternativ åtgärd skulle vara att prova att tillsätta svavel som additiv med bränslet. Det har visat sig ge bra resultat i tidigare studier.

  • 83.
    Bonthron, Jonatan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Förstudie för etablering av vindkraft vid Dåva kraftvärmeverk2011Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 84.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Grimm, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering.
    Ash transformation chemistry during energy conversion of biomass2010In: Impacts of Fuel Quality on Power Production & Environment: 29/08/2010 - 03/09/2010, Impacts of Fuel Quality , 2010Conference paper (Refereed)
    Abstract [en]

    There is relatively extensive knowledge available concerning ash transformation reactions during energy conversion of woody biomass. Traditionally, these assortments have constituted the main resources for heating in Sweden. In recent decades the utilization of these energy carriers has increased, from a low technology residential small scale level to industrial scale (e.g. CHP plants). Along this evolution ash-chemical related phenomena for woody biomass has been observed and studied. So, presently the understanding for these are, if not complete, fairly good. Briefly, from a chemical point of view the ash from woody biomass could be characterized as a silicate dominated systems with varying content of basic oxides and with relatively high degree of volatilization of alkali sulfates and chlorides. Thus, the main ash transformation mechanisms in these systems have been outlined. Here, an attempt to give a general description of the ash transformation reactions of biomass fuels is presented, with the intention to provide guidance in the understanding of ash matter behavior in the utilization of any biomass fuel, primarily from knowledge of the concentrations of ash forming elements but also by considering the physical condition in the specific combustion appliance and the physical characteristic of the biomass fuel. Furthermore, since the demand for CO2-neutral energy resources has increased the last years and will continue to do so in the foreseeable future, other biomasses as for instance agricultural crops has become highly interesting. Globally, the availability of these shows large variation. In Sweden, for instance, which is a relatively spare populated country with large forests, these bio-masses will play a secondary role, although not insignificant. In other parts of the world, more densely populated and with a large agricultural sector, such bio-masses may constitute the main energy bio-mass resource in the future. However, the content of ash forming matter in agricultural bio-mass is rather different in comparison to woody biomass. Firstly, the content is much higher; from being about 0.3 – 0.5% (wt) in stem wood, it can amount to between 2 and 10 %(wt) in agricultural biomass. In addition, the composition of the ash forming matter is different. Shortly, the main difference is due to a much higher content of phosphorus (occasionally also silicon) which has major consequences on the ash-transformation reactions. In many crops, the concentration of phosphorus and silicon is equivalent, which (depending on the concentration levels of basic oxides) may result in a phosphate dominated ash. The properties of this ash are in several aspects different from the silicate dominated woody biomass ash and will consequently behave differently in various types of energy conversion systems. The knowledge about phosphate dominated ash systems has so far been scarce. We have been working with these systems, both with basic and applied research, for about a decade know. Some general experiences and conclusions as well as some specific examples of our research will be presented.

  • 85.
    Boström, Dan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Grimm, Alejandro
    Luleå Univ Technol, Div Energy Sci, SE-97187 Luleå, Sweden.
    Boman, Christoffer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå Univ Technol, Div Energy Sci, SE-97187 Luleå, Sweden.
    Broström, Markus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Backman, Rainer
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ash Transformation Chemistry during Combustion of Biomass2012In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 26, no 1, p. 85-93Article in journal (Refereed)
    Abstract [en]

    There is relatively extensive knowledge available concerning ash transformation reactions during combustion of woody biomass. In recent decades, the use of these energy carriers has increased, from a low-technology residential small-scale level to an industrial scale. Along this evolution, ash chemical-related phenomena for woody biomass have been observed and studied. Therefore, presently the understanding for these are, if not complete, fairly good. However, because the demand for CO2-neutral energy resources has increased recently and will continue to increase in the foreseeable future, other biomasses, such as, for instance, agricultural crops, have become highly interesting. The ash-forming matter in agricultural biomass is rather different in comparison to woody biomass, with a higher content of phosphorus as a distinctive feature. The knowledge about the ash transformation behavior in these systems is far from complete. Here, an attempt to give a schematic but general description of the ash transformation reactions of biomass fuels is presented in terms of a conceptual model, with the intention to provide guidance in the understanding of ash matter behavior in the use of any biomass fuel, primarily from the knowledge of the concentrations of ash-forming elements. The model was organized in primary and secondary reactions. Restrictions on the theoretical model in terms of reactivity limitations and physical conditions of the conversion process were discussed and exemplified, and some principal differences between biomass ashes dominated by Si and P, separately, were outlined and discussed.

  • 86. Bozaghian, Marjan
    et al.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Thyrel, Mikael
    Xiong, Shaojun
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Engineering, S-971 87 Luleå, Sweden.
    Combustion characteristics of straw stored with CaCO3 in bubbling fluidized bed using quartz and olivine as bed materials2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 212, p. 1400-1408Article in journal (Refereed)
    Abstract [en]

    The addition of Ca-containing compounds can reduce mass loss from agricultural biomass during storage. The resulting alkaline environment is detrimental to microorganisms present in the material. Theoretical analysis of Ca-containing biomass suggests that combustion properties are improved with respect to slagging. To validate the theoretical calculations, barley straw was utilized as a typical model agricultural biomass and combustion characteristics of straw pre-treated with 2 and 4 w/w% CaCO3 for combined improvement of storage and combustion properties were determined through combustion at 700 degrees C in a bench-scale bubbling fluidized-bed reactor (5 kW) using quartz and olivine sand as bed materials. The combustion characteristics were determined in terms of elemental composition and compound identification in bed ash and bed material including agglomerates, fly ash, particulate matter as well as flue gas measurements. The addition of CaCO3 to straw had both positive and negative effects on its combustion characteristics. Both additive levels raised the total de fluidization temperature for both quartz and olivine, and olivine proved to be less susceptible than quartz to reactions with alkali. With Ca-additives, the composition of deposits and fine particulate matter changed to include higher amounts of KCl potentially leading to higher risk for alkali chloride-induced corrosion. Flue gas composition was heavily influenced by CaCO3 additives by significantly elevated CO concentrations likely related to increased levels of gaseous alkali compounds. The results suggest that it is necessary to reduce gaseous alkali compounds, e.g. through kaolin or sulphur addition, if alkali-rich straw is to be co-combusted with Ca-rich biomass or large amounts of Ca-additives.

  • 87.
    Bozaghian, Marjan
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Xiong, Shaojun
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion characteristics of barley straw stored with CaCO3 using olivine and quartz as bed materials in fluidized bed combustion2017Conference paper (Refereed)
  • 88.
    Bozaghian, Marjan
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Rebbling, Anders
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Larsson, Sylvia H.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Xiong, Shaojun
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Combustion characteristics of barley straw stored with CaCO3 using quartz and olivine as bed materials in fluidized-bed combustion2017Conference paper (Other academic)
  • 89.
    Breimark, Odd
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Undersökning av förutsättningar för icke-publik laddinfrastruktur2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis is done as an assignment on behalf of Luleå Energi AB and Luleå Energi Elnät AB. It mainly concerns charging of Plug-in electric vehicles at corporations and apartment buildings. The object of this thesis is to investigate current requirements with these users and to investigate how services can be constructed to fulfil these requirements.

    To investigate the requirements of this non-public market a series of interviews were performed. A number of questions were constructed to use as ground during the interviews. Apart from the constructed questions, the interviewed were encouraged to express other opinions and questions concerning charging of electric vehicles. A large interest exists concerning this mater and several corporations are already offering charging although it also shows that a wider non-public infrastructure is required. The interviews also revealed that a wide spread of information is of importance and that charging with an ordinary home outlet (Schuko) is not to be recommended. All of the interviewed were of the opinion that more information from Luleå Energi would be of interest and that this would promote the expansion of electric vehicles.

    An extensive theory chapter was constructed to cover questions that may appear during the work of the thesis. This enabled a spread of information during the interviews. This chapter is meant to be used as information at Luleå Energi but could also be used as information to future clients. A number of criteria were constructed with the interviews and the theory chapter as foundation. These criteria were then given a weight of importance to present the aspects to bear in mind when implementing charge stations. The criteria that concerned standards and safety were the most important ones, along with the criteria of the impotence of an energy meter to every charging point. Criteria that where of importance but not as much as those mentioned earlier were limited access only to specific users, economical aspects, user friendly functions and effective payment systems. A confident ownership was of importance whereas some kind of service agreement could be of interest. Aspects of low importance were those connected to design but also the aspect that a connection for engine heaters is available.

    Charging of electric vehicles at apartment buildings and corporations will most likely not exceeded an output of 7.4 kW due to the fact that cars spend most of their time at parking spaces. These chargers could be complimented with chargers with a higher output up to 22 kW. The benefits of higher outputs appear when clients or workers spend a short time at a charging site. Quick chargers with outputs from 50 kW are rarely of economic benefit due to the high cost of the equipment and installation.

    A series of tests where concluded with a battery electric vehicle with the purpose to investigate energy consumption in Nordic winter climate. Temperature, travelled distance and energy consumption where the main parameters of the tests. The tests included both country road testing and city road testing. The tests resulted in a higher energy consumption and shorter range compared to the numbers presented from the car manufacturer. Despite this the test revealed that the range is enough in most of the cases with daily travel. The greatest advantages compared to fossil fuel vehicles appeared in city traffic where this particular vehicle could be driven in 3.5 hours without recharging. All together this reveals the economic and environmental advantages of driving a battery electric vehicle compared to a fossil fuel vehicle.

  • 90.
    Brembilla, Christian
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Soleimani-Mohseni, Mohsen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Olofsson, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Transient model of a panel radiator2015In: Proceedings of BS2015: 14th Conference of International Building Performance Simulation Association, Hyderabad, India, Dec. 7-9, 2015, India, Hyderabad: International Building Performance Simulation Association (IBPSA), 2015, , p. 2749-2756p. 2749-2756Conference paper (Refereed)
    Abstract [en]

    This paper shows a transient model of a hydronic panel radiator modelled as a system of multiple storage elements. The experiment´s results suggest the more suitable technique for modelling this technology. The panel radiator is modelled numerically with eight thermal capacitance connected in series by keeping a memory of the heat injected in the thermal unit. The comparison of the performance among lumped steadystate models and transient model, in terms of heat emission and temperature of exhaust flow, shows the potential of the latter approach. To conclude, (1) the transient phase is essential for modelling stocky panels, and (2) this type of modelling has to be addressed for evaluating the performance of low energy buildings.

  • 91.
    Brännstam, Johanna
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Molnbaserade CAD-system2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When working with computer-aided design (CAD), are you tired of CAD-files being saved, where you cannot access them? Are you tired of having to sit at a specific computer to work on your drawings? Recently, cloud-basedCAD software started to become available and companies, such as Umeå-based Sigma Industry East/North, consider settling on a standard cloud-basedor cloud-connected program to facilitate the work of theirconsultants. In this bachelor thesis, two of the most promising cloud-basedCAD programs, Autodesk Fusion 360 and Onshape, are selected among the available CAD software, and investigatedwith respect to parameters such as price, program handling, user education, folder structure and archiving, and the ability to perform finite element method (FEM) analysis. In order to substantiate the evaluation, the two programs are exposed to a test. A generic work piece is modeled and drawn that allows comparison regarding multicomponent modeling, sheet metal, drawings, threads and text engraving. It was found that, in general, the two different programs perform similarly, but that they differ in at least three important aspects: price, ability to work offline and user ability. Fusion 360 costs half the price of a comparable Onshape license, can be payed monthly, does not require internet, and allows the cost FEM functions to be individually adapted. Basedon this analysis, Fusion 360 is recommended as cloud-based CAD-software for small-to medium-sized companies.

  • 92.
    Brännström, Emil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Underlag för kommunal- respektive gårdsbaserad biogasanläggning.2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 93.
    Burck, Robin
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ENERGIEFFEKTIVISERING AV VENTILATIONSYSTEM I AITIK, BOLIDEN2015Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    The mine of Aitik is the largest open cast mine in Sweden that refines chalcopyrite. The chalcopyrite is being transported from the open cast mine beneath through a system of underground tunnels to a refinery above ground. There is a ventilation system in the tunnels that is controlled without knowledge of the requirement of ventilation’s force. Boliden has the intention of doing energy saving’s within the corporation. One alternative to save energy is to steer the ventilation. There’s an application called “Ventilation on demand” that steers the airflow of ventilation systems, which can be implemented in the current steering system 800xA. The concept of the application is to minimize the use of energy and both the application and steering system is a product of ABB. Before the implementation of the application a pilot study is needed to chart the airflow based on the requirement to sustain good working environment in the tunnels. The pilot study will contain a situation analysis and a series of measurements with different ventilation speeds. The result of measurement will tell how the ventilation speed affects the air quality in the tunnels and energy use of fans and district heating. The pilot study will also contain the result of cost- and energy savings by installing the application. ‘  The ventilation system contains five fans and two of them have frequency inverters. The air that is forced down to the system of tunnels is heated by district heating trough heating batteries. Skellefteå Kraft is the supplier of the district heating and the pellet boiler is located within the mining area. The situation analysis will be a reference to compare the series of measurements and present the possibilities of cost- and energy savings regarding the working environment in the tunnels.  The result demonstrates the possibilities of making energy savings up to sixty percent and still have a good working environment. The result also demonstrate that “Ventilation on demand” has a short payback time.

  • 94.
    Bychkov, Vitaly
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Modestov, Mikhail
    Law, Chung K.
    Combustion Phenomena in Modern Physics: I. Inertial Confinement Fusion2015In: Progress in Energy and Combustion Science, ISSN 0360-1285, E-ISSN 1873-216X, Vol. 47, p. 32-59Article, review/survey (Refereed)
    Abstract [en]

    The overarching objective of the present endeavor is to demonstrate the universal character of combustion phenomena for various areas of modern physics, focusing on inertial confinement fusion (ICF) in this review. We present the key features of laser deflagration, and consider the similarities and differences between the laser plasma flow and the slow combustion front. We discuss the linear stage of the Rayleigh-Taylor instability in laser ablation, short-wavelength stabilization of the instability due to the mass flow, and demonstrate the importance of the concepts and methods of combustion science for an understanding of the corresponding ICF processes. We show the possibility of the Darrieus-Landau instability in the laser ablation flow and discuss the specific features of the instability at the linear and nonlinear stages as compared to the combustion counterpart of this phenomenon. We consider the nonlinear stage of the Rayleigh-Taylor instability in the ICF and generation of ultra-high magnetic field by the instability, and show that proper understanding of vorticity production in the laser plasma and, hence, of the magnetic field generation requires concepts from combustion science.

  • 95.
    Bychkov, Vitaly
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Sadek, Jad
    Akkerman, V'yacheslav
    Analysis of flame acceleration in open or vented obstructed pipes2017In: PHYSICAL REVIEW E, ISSN 2470-0045, Vol. 95, no 1, article id 013111Article in journal (Refereed)
    Abstract [en]

    While flame propagation through obstacles is often associated with turbulence and/or shocks, Bychkov et al. [V. Bychkov et al., Phys. Rev. Lett. 101, 164501 (2008)] have revealed a shockless, conceptually laminar mechanism of extremely fast flame acceleration in semiopen obstructed pipes (one end of a pipe is closed; a flame is ignited at the closed end and propagates towards the open one). The acceleration is devoted to a powerful jet flow produced by delayed combustion in the spaces between the obstacles, with turbulence playing only a supplementary role in this process. In the present work, this formulation is extended to pipes with both ends open in order to describe the recent experiments and modeling by Yanez et al. [J. Yanez et al., arXiv: 1208.6453] as well as the simulations by Middha and Hansen [P. Middha and O. R. Hansen, Process Safety Prog. 27, 192 (2008)]. It is demonstrated that flames accelerate strongly in open or vented obstructed pipes and the acceleration mechanism is similar to that in semiopen ones (shockless and laminar), although acceleration is weaker in open pipes. Starting with an inviscid approximation, we subsequently incorporate hydraulic resistance (viscous forces) into the analysis for the sake of comparing its role to that of a jet flow driving acceleration. It is shown that hydraulic resistance is actually not required to drive flame acceleration. In contrast, this is a supplementary effect, which moderates acceleration. On the other hand, viscous forces are nevertheless an important effect because they are responsible for the initial delay occurring before the flame acceleration onset, which is observed in the experiments and simulations. Accounting for this effect provides good agreement between the experiments, modeling, and the present theory.

  • 96.
    Bygdén, Olov
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Testpiloter i praktisk energieffektivisering: Visualisering och kommunikation2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete har utförts på Skellefteå Kommuns fastighetsavdelning under hösten 2012 och även under början på 2013. Fastighetsavdelningen är ansvariga för bl.a. driften hos Skellefteå Kommuns byggnader och därmed också ansvariga för att minska energianvändningen hos dessa. Till år 2016 har Skellefteå Kommun som mål att åstadkomma en energieffektivisering på 20 % jämfört med utgångsåret 2009. Detta projekt har utförts som en del av detta energieffektiviseringsarbete.

     Projektet omfattar två olika mätperioder, under den andra av dessa mätperioder installerades visualiseringsskärmar hos de två berörda objekt som utvalts till detta projekt. På visualiseringsskärmarna visades sedan den momentana energiförbrukningen för att brukarna skulle kunna hålla koll på om förbrukningen ökade eller minskade sett till den senaste veckan. Två informationsträffar, en för varje arbetsplats, hölls också för att informera om projektet samt att ge tips på tänkbara förändringar i arbetsmetoderna som skulle kunna medföra minskad energiförbrukning och därigenom ett positiv resultat.

    Resultatet av detta projekt blev en mängd mätdata som har sammanställts och analyserats för att slutligen resultera i ett utfall i form av att det ena objektet minskade sin energiförbrukning med 1,7 % och det andra objektet med hela 24,2 %.

    Slutsatsen har därmed blivit att visualisering samt kommunikation kan vara ett tänkbart alternativ till att åstadkomma en minskad energianvändning och motivera brukare av lokaler att bli engagerade och bidra själva.

  • 97.
    Bäckström, Johan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Optimerad värmeleverans från Hedensbyverket2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Skellefteå Kraft AB has currently problems with the central district heating network in Skellefteå concerning low pressure difference between the delivering, hot, and returning, cold, pipeline. Cause of this low so called differential pressure, the customers heating requirements in these areas is not fulfilled in a satisfying way. The intent of this project has been, with the use of simulations, to clarify if a solution can be possible by connecting an increasing pressure pump to the district heating network. A pumpstation will be placed in such a way that it improves the ability to control the pressurization of the district heating pipelines and also makes it possible to distribute more heat from Hedensbyn, where the main production of district heat in Skellefteå takes place. Determine if the increase in pressure may result in an increase in electricity production, by lowering the temperature of the outgoing water.

    The result is this project shows that placing a pumpstation at Moröskolan is the most advantageous position. An increasing pressure pump at Moröskolan in Skellefteå would create more favourable conditions in order to control the pressure in the district heating network and maintain a minimum differential pressure. The simulations made shows that with a pumpstation, it is possible to distribute up to 20 MW more heat from the Hedensbyn. A pressure increase in the district heating network would currently allow for an increase in electricity distribution of approximately 4-5,5 GWh/year. Based on these results, the project concerning the pump is planned to begin during spring 2011.

  • 98.
    Bäckström, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Guilloux, Tom
    Fusing Kite and Tether into one Unit2017In: Airborne Wind Energy Conference 2017: Book of Abstracts / [ed] Moritz Diehl, Rachel Leuthold, Roland Schmehl, Freiburg, Germany: Albert-Ludwigs-Universität Freiburg; Delft University of Technology , 2017, p. 40-41Conference paper (Refereed)
  • 99.
    Bäckström, Marcus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Pneumatisk Dragprovmaskin: För uppmätning av separationskrafter för skogsplantor från deras kassetter i samband med plantering vid olika förhållanden.2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Bracke Forest AB tillverkar maskinella planteringsaggregat som utvecklas för en modernare och en mer noggrann skogsplantering. Deras planteringsaggregat har ett begränsat antal platser i hållaren som lagrar plantorna innan de sätts i marken. Aggregatet laddas med nya plantor manuellt av skogsmaskinens operatör, där en planta flyttas från dess kassett till hållaren. En process som Bracke Forest AB planerar att förändra på nästa generations planteringsmaskiner.

    Syftet med detta examensarbete är att ta reda på vilka krafter som uppstår vid lyft av planta från dess kassett, vilket ska ligga som underlag vid utvecklingen. I detta examensarbete testas olika kassetter där snabba och långsamma hastigheter jämförs vid blöta och återbevattnade förhållanden, för att ta reda på vilken kassett som lämpar sig bäst för automatisk hantering. Examensarbetet begränsas till gran och tall där de tre kassetterna Hiko, Jackpot och Starpot från respektive skogsbolag analyseras.

    En egenkonstruerad pneumatisk dragprovmaskin tillverkas och med hjälp av en analog tryckgivare registreras tryckskillnaden via ett styrkort, Arduino Mega 2560. Tryckskillnaden beräknas om till kraft och ett resultat i form av tabeller och diagram tas fram. För att kontrollera att den egenkonstruerade dragprovmaskinen redovisar relevanta resultat används en befintlig dragprovmaskin som referens. Detta examensarbete berör pneumatik, 3D-konstruktion i Solidworks, elektronik, Arduino programmering, tillverkning och grafisk analys av analog signaldata.

    Resultatet från dragproven visar att Starpot kassetten kräver minst medelkraft för lyft av en planta från dess kassett. På grund av att rötterna för både Starpot och Jackpot kunde fastna i kassetten och gå av vid dragningarna är rekommendationen att använda Hiko-kassetten, då dess plantor kan dras vid olika hastigheter utan att rotdelning uppstod.

  • 100.
    Bäfver, Linda
    et al.
    Pöyry SwedPower.
    Renström, Caroline
    Pöyry SwedPower.
    Fahlström, Johan
    Ragn-Sells.
    Enfält, Patrik
    EasyMining Sweden.
    Skoglund, Nils
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmén, Erik
    ENA Energi.
    Slambränsleblandningar: Förbränning och fosforutvinning2013Report (Other academic)
    Abstract [en]

    For sustainable phosphorus recycling, the phosphorus in sewage sludge needs to be recovered, as it is a major phosphorus-source. However, all sludge is not suitable for direct recycling on agricultural land, e.g. when the content of heavy metals is too high. To achieve an increased recycling of phosphorus from sewage sludge there is a need of research and development of alternative methods to return the phosphorus from sewage sludge to agricultural land.

    The aim of the project is to show that sewage sludge can be co-combusted with demolition wood in existing boilers, and that the ash can be processed for extraction of phosphorus, together with valuable by-products from the process. Further effects of the project will be the development of new knowledge about combustion with a high sludge to demolition wood ratio in a grate boiler (up to 45 % sludge with respect to wet mixture), which has not been studied in full-scale combustion earlier. The project's goal is to demonstrate mixing and combustion of fuel mixtures of sludge and demolition wood, and subsequent extraction of phosphorus from ash. The target groups for this work are energy companies, suppliers of grate boilers, municipalities, wastewater treatment plants and authorities.

    The project involves the mixing of sewage sludge and demolition wood, combustion-tests of the fuel mixtures and laboratory experiments on bottom ash and fly ash for phosphorus extraction using EasyMining Sweden's method for phosphorus extraction from ash. Extensive analyses have been carried out on fuel, bottom ash and fly ash, as well as thermodynamic equilibrium calculations on the formed compounds containing phosphorus.

    The experience of preparing sludge fuel mixtures shows that the mixtures should be prepared in the near future to when they are to be combusted, to avoid a composting process in the fuel. The project shows that it is possible to combust sludge fuel mixtures with an admixture of up to 45 % sludge relative wet fuel, in an existing grate boiler during one day. However, to combust sludge fuel mixtures over a longer period of time and at a higher load, modifications of the de-ashing system and the flue gas cleaning system are needed. The results indicate a reduced tendency of slagging on the fuel bed at the combustion of sludge mixtures. The analyses of the fly ash showed a trend towards less corrosive ash at combustion of sludge mixtures. The phosphorus content in the ash in this work was 3-4 %. For process economics and from the phosphorus extraction point, as high phosphorus content as possible in the ash is preferable. Higher phosphorus content can be accomplished by mixing sludge with a fuel with lower ash content than demolition wood, co-combustion with a fuel with higher phosphorus content than demolition wood, or by increasing the percentage of sewage sludge in the fuel mixture. Still, a higher proportion of sludge in the mixture would require a higher dry matter content of the sludge in order to get proper combustion conditions. It is primarily bottom ash that is suitable for phosphorus extraction using Easy Mining Sweden's method. If fly ash are to be used for phosphorus extraction, an optimization of the dissolution conditions is required, which was not included in this project. In this project, phosphorus is extracted as ammonium phosphate. The purity of ammonium phosphate is very high, which means that unwanted substances and heavy metals in sewage sludge will not be returned to contaminate fields.

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