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  • 1.
    Akkerman, Vyacheslav
    et al.
    West Virginia University, Morgantown, WV, United States.
    Bilgili, Serdar
    West Virginia University, Morgantown, WV, United States.
    Bychkov, Vitaly
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Demir, Sinan
    West Virginia University, Morgantown, WV, United States.
    Morella, Haley
    West Virginia University, Morgantown, WV, United States.
    Impacts of the Lewis and Markstein numbers effects on the flame acceleration in channels2016In: 2016 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2016, Eastern States Section of the Combustion Institute , 2016Conference paper (Refereed)
    Abstract [en]

    The effects of flame stretch and thermal/molecular diffusion on the flame acceleration in channels are quantified by means of the analytical and computational endeavours. The internal transport flame properties are accounted in the theory by means of the Markstein number, Mk. Being a positive or negative function of the thermal-chemical combustion parameters, such as the thermal expansion ratio and the Lewis and Zeldovich numbers, the Markstein number either moderates or promotes the flame acceleration. While Mk may provide a substantial impact on the flame acceleration rate in narrow channels, this effects diminishes with the increase of the channel width. The analysis is accompanied by extensive computational simulations of the Navier-Stokes combustion equations, which clarify the impact of the Lewis number on the flame acceleration. It is obtained that, for Le below a certain critical value, at the initial stage of flame acceleration, a globally-convex flame front is splits into two or more "fingers", accompanied by a drastic increase in the flame surface area and associated enhancement of the flame acceleration. Overall, the thermal-diffusive effects substantially facilitate the flame acceleration scenario, thereby advancing a potential deflagration-to-detonation transition. 

  • 2.
    Akkerman, Vyacheslav
    et al.
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV, United States .
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effect of gas compression on flame acceleration in obstructed cylindrical tubes2016In: 2016 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2016, Eastern States Section of the Combustion Institute , 2016Conference paper (Refereed)
    Abstract [en]

    The role of gas compression on the process of extremely fast flame acceleration in obstructed cylindrical tubes is studied analytically and validated by computational simulations. The acceleration leading to a deflagration-to-detonation transition is associated with a powerful jet-flow produced by delayed combustion in spaces between the obstacles. This acceleration mechanism is Reynolds-independent and conceptually laminar, with turbulence playing only a supplementary role. In this particular work, the incompressible formulation [Combust. Flame 157 (2010) 1012], Ref. 15 is extended to account for small but finite initial Mach number up to the first-order terms. While flames accelerate exponentially during the initial stage of propagation, when the compressibility is negligible, with continuous increase in the flame velocity with respect to the tube wall, the flame-generated compression waves subsequently moderate the acceleration process by affecting the flame shape and velocity, as well as the flow driven by the flame. It is demonstrated that the moderation effect is substantial, and as soon as gas compression is relatively small, the present theory is in good quantitative agreement with the computational simulations. The limitations of the incompressible theory are thereby underlined, and a critical blockage ratio for with this acceleration mechanism can be evaluated.

  • 3.
    Arbuthnott, Andrew
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business.
    Eriksson, Jessica
    Umeå University, Faculty of Social Sciences, Umeå School of Business.
    Wincent, Joakim
    Umeå University, Faculty of Social Sciences, Umeå School of Business.
    When a new industry meets traditional and declining ones: An integrative approach towards dialectics and social movement theory in a model of regional industry emergence processes2010In: Scandinavian Journal of Management, ISSN 0956-5221, E-ISSN 1873-3387, Vol. 26, no 3, 290-308 p.Article in journal (Refereed)
    Abstract [en]

    This paper takes an integrative approach towards dialectics and social movement theories in a model of regional industry emergence processes. Based on an inductive qualitative investigation we describe how a new industry emerges in a declining and peripheral region dominated by struggling and traditional local industry. The emanating model of regional industry emergence is based on four main processes; framing processes, movement mobilisation processes,inter-industry relational processes and dialectical processes, which together shape the emerging regional industry. This exemplifies how new regional industry mobilisation efforts provide an ‘anti-thesis’ to traditional industry, and how established industry actors respond with contestation to protect their business concepts. Furthermore we illustrate how new industry actors reframe their concepts to complement dominating traditional industry and to overcome tensions and conflicts. Following dialectic interaction between new and traditional industry wenoticed signs of acceptance and synthesis between the newly formed and old industry actors; ultimately resulting in a revitalisation of the region’s traditional industry. As such, this article makes a point of accounting for agency and productive conflict when understanding regional industry renewal and emergence.

  • 4.
    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.

  • 5.
    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.

  • 6.
    Dion, Claude
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Demirgok, Berk
    Dept. Mechanical and Aerospace Engineering, West Virginia University, 26506 Morgantown, USA.
    Akkerman, Vyacheslav
    Dept. Mechanical and Aerospace Engineering, West Virginia University, 26506 Morgantown, USA.
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bychkov, Vitaly
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Acceleration and Extinction of Flames In Channels With Cold Walls2015In: Proceedings of the 25th International Colloquium on the Dynamics of Explosions and Reactive Systems / [ed] M.I. Radulescu, 2015Conference paper (Refereed)
  • 7.
    Eriksson, Torbjörn
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konfigurerbar och portabel simulatorhårdvara: Framtagning av koncept2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Based in Umeå, Sweden, Oryx Simulations is looking to explore the possibilities to produce a concept of a set of modularized desktop simulation hardware. Based on a common platform, the idea is to increase ease of setting up the hardware according to chosen simulation.

    The project is managed with a subset of the agile development method, modified for product concept development.

    The final concept is a modularized hardware platform that is relatively easy to configure to suit the chosen simulation. 

  • 8.
    Gruber, Andrea
    et al.
    SINTEF Energy Research, 7465 Trondheim, Norway.
    Chen, Jacqueline H.
    Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA.
    Valiev, Damir
    Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA.
    Law, Chung K.
    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA.
    Direct numerical simulation of premixed flame boundary layer flashback in turbulent channel flow2012In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 709, 516-542 p.Article in journal (Refereed)
    Abstract [en]

    Direct numerical simulations are performed to investigate the transient upstream propagation (flashback) of premixed hydrogen–air flames in the boundary layer of a fully developed turbulent channel flow. Results show that the well-known near-wall velocity fluctuations pattern found in turbulent boundary layers triggers wrinkling of the initially flat flame sheet as it starts propagating against the main flow direction, and that the structure of the characteristic streaks of the turbulent boundary layer ultimately has an important impact on the resulting flame shape and on its propagation mechanism. It is observed that the leading edges of the upstream-propagating premixed flame are always located in the near-wall region of the channel and assume the shape of several smooth, curved bulges propagating upstream side by side in the spanwise direction and convex towards the reactant side of the flame. These leading-edge flame bulges are separated by thin regions of spiky flame cusps pointing towards the product side at the trailing edges of the flame. Analysis of the instantaneous velocity fields clearly reveals the existence, on the reactant side of the flame sheet, of backflow pockets that extend well above the wall-quenching distance. There is a strong correspondence between each of the backflow pockets and a leading edge convex flame bulge. Likewise, high-speed streaks of fast flowing fluid are found to be always colocated with the spiky flame cusps pointing towards the product side of the flame. It is suggested that the origin of the formation of the backflow pockets, along with the subsequent mutual feedback mechanism, is due to the interaction of the approaching streaky turbulent flow pattern with the Darrieus–Landau hydrodynamic instability and pressure fluctuations triggered by the flame sheet. Moreover, the presence of the backflow pockets, coupled with the associated hydrodynamic instability and pressure–flow field interaction, greatly facilitate flame propagation in turbulent boundary layers and ultimately results in high flashback velocities that increase proportionately with pressure.

  • 9.
    Gruber, Andrea
    et al.
    SINTEF Energy Research, Trondheim, Norway.
    Kerstein, Alan R.
    SINTEF Energy Research, Trondheim, Norway.
    Valiev, Damir
    Combustion Research Facility, Livermore, CA, United States.
    Law, Chung K.
    Princeton University, Princeton, NJ, United States.
    Kolla, Hemanth
    Combustion Research Facility, Livermore, CA, United States.
    Chen, Jacqueline H.
    Combustion Research Facility, Livermore, CA, United States.
    Modeling of mean flame shape during premixed flame flashback in turbulent boundary layers2014In: Proceedings of the Combustion Institute, ISSN 0082-0784, E-ISSN 1878-027XArticle in journal (Refereed)
    Abstract [en]

    Direct numerical simulations of freely-propagating premixed flames in the turbulent boundary layer of fully-developed turbulent channel flows are used for a priori validation of a new model that aims to describe the mean shape of the turbulent flame brush during flashback. Comparison with the DNS datasets, for both fuel-lean and fuel-rich mixture conditions and for Damköhler numbers lower and larger than unity, shows that the model is able to capture the main features of the flame shape. Although further a priori and a posteriori validation is required, particularly at higher Reynolds numbers, this new simple model seems promising and can potentially have impact on the design process of industrial combustion equipment.

  • 10.
    Janse, Joakim
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konceptdesign av låsmekanism till frontlastare2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Följande rapport behandlar en konceptutveckling av en låsmekanism vars syfte är att låsa fast en frontlastare mot en traktor. Arbetet är utfört på Ålös produktutvecklingsavdelning i Brännland. Bakgrunden till arbetet är att Ålö har ett intresse i att uppdatera dagens lösning på låsmekanismen med en ny design och ta fram en lösning som är mer kompakt och mer hållfast. Det nya konceptet skulle också vara bakåtkompatibelt så inga modifieringar fick göras på någon av detaljerna där låsmekanismen är infäst, det vill säga samma infästningshål som används idag skall även användas till konceptet.För att underlätta arbetet undersöktes dagens låsmekanism och eventuella problem som finns med denna. Det visade sig då att en stor del av dagens reklamationer beror på felaktig montering av låsmekanismen.Tre olika koncept togs fram. Av dessa valdes det mest realistiska alternativet ut för vidare arbete. Materialval gjordes på varje ingående komponent med avseende på bland annat pris och bearbetningsmetod. Konceptet jämfördes sedan storleksmässigt mot dagens mekanism med hjälp av CAD-programvaran. I denna jämförelse visade det sig att konceptet har en lägre bygghöjd jämfört med dagens lösning. Tre teoretiska lastfall beräknades och utifrån dessa utfördes en finita elementanalys av både dagens mekanism och konceptet i CAD programmet. I denna analys blev det bekräftat att konceptet kan bära högre laster. En fysisk modell i plast togs fram med en 3D skrivare och denna användes för att utvärdera mekanismens ergonomi och för att få en bättre bild av designen. Efter en utvärdering av konceptet utfördes mindre ändringar i konstruktionen.En monteringsinstruktion till mekanismen togs fram. Tanken med denna monteringsanvisning var att minska risken för felaktig montering, detta för att undvika framtida reklamationer.

  • 11.
    Jansson, Victor
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Konstruktion av skivstänger: Ett tillverkningsunderlag för sex olika typer av skivstänger2017Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
    Abstract [en]

    Lars Norberg with his company Balticfitness wants to compete with the largest companies on the market for barbells, wanting to make the best ones. By starting to manufacture their own bars and sell in their store. The project is about finding six different types of barbells that Lars wants to produce; IWF mens and women’s, Crossfit mens and women’s, IPF and a technical bar. The goal is to produce a manufacturing basis for all of the bars. The project is divided on two people, me and Filip Holmberg. I took responsibility for the choice of materials, knurls and surface treatment, while Filip took responsibility for the bearing solution and the sleeves.

     

    To select materials for the bars that met the requirements, many companies were contacted to hear what they recommended. By using the information from the companies that were contacted, it was concluded that one of these steels would be appropriate; SS 2541 (356Q) from Ovako, Uddeholm Deivar or Uddeholm Unimax. In the end, Ovako's SS 2541 (356Q) was chosen as it would need the least manufacturing steps, yet good enough strength. To find out if the material would handle the stresses it will be exposed to, FEM analysis was used in the program Solidworks.

     

    The choice of knurl is different for each bar but all bars have cross-sectional pattern. The grip for each bar; IWF bars were chosen to be medium, the Crossfit and technic bars to mild and IPF bar to rough.

     

    The surface treatment was selected for chrome plating for all bars except for the IPF and technic bars. These bars did not get any surface treatment at all.

     

    In the end the project was successful and most of the requirements were met. The only requirements that were not achieved were the strength of the women’s barbells. In practice, however, the bars will handle sufficient loads without any problems.

  • 12.
    Lindehag, Samuel
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Rotationsdämpare med integrerad fjäder2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This final thesis is carried out at BAE Systems Hägglunds in Örnsköldsvik. The mission was to construct and integrate a new semi-active damping unit in the terrain vehicle BvS10. Questions that came up during the process, among others, was how to mount the damping unit to the vehicle in a flexible way without exposing it to unnecessary wears.

    A generation of the concept is made in 3D using CATIA V5 of a possible solution to the problem. The idea is to weld the unit to the skid girder which is one of the main constructions of the track system. In this way the damping unit will come closer to the track system, which will partly protect it from impacts from below and minimize current problems with breaking forces in the torsion shafts.

    The complete construction was then analyzed, first by theoretical calculations and then with the FEM-tools in CATIA V5. The result of this analysis showed that the construction had a good potential to resist deformation and high tensions. Drawings in 2D of the assemblies were then generated for the left and right damping units separately.

  • 13.
    Ljungberg, Dennis
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gjutoptimering av svetsat QSD60-fäste: Förstudie för gjutning av ett svetsat redskapsfäste på engcon tiltrotator2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Engcon Nordic AB is a company located in Strömsund, Sweden, and is a part of the engcon Group. Engcon is a global leader company in the manufacture of tiltrotators and tool attachment for excavators. The tiltrotators produced at engcon, are manufactured after the customer needs, with the alternative to choose between different sizes, fittings and tool attachments. At this time engcon are developing a new type of hitch for attachment of a integrated grabber, referred to as QSD60-hitch. This QSD60-hitch which allows attachment of a integrated grabber is today planned to be manufactured by welding of a set of pree-cut and machined steel plates, along with a newly developed integrated hydraulic block for control of the gripping claws. This method of manufacturing, with welding of plates, is a very time consuming and expensive method to use for this reason. Engcon Nordic AB has engaged me to investigate whether it is possible to use metal casting of this hitch instead of welding. The purpose of this project is to gather information and put together an early pilot studie of how to manufacture the hitch with casting, based on which of the avalible casting methods that should be used, what materials that are suitable for this purpose and if possible, make suggestions of how to change the shaping and design of the hitch to optimize to the selected casting method. This project is divided into three parts. The very first part consist of gathering information about the various casting methods that are avalible today, and what materials to choose between. Thereafter, the gathered information are used to come up with a proposal of what material and casting method that should be used with consideration of the design and shape of the hitch and the material requirements. The second part of this work is based on finding out how the casting of this object should be done for the chosen method, whether it should be casted in one piece or if separate pieces are necessary, and with respect to the required machining in consideration. Finally the last part of this work consists of making an approximate calculation of the unit price of this hitch, for the alternative casting manufacturing.

  • 14.
    Lundström, Viktoria
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Virtual Commissioning: Virtual Commissioning of ABB Production cell2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The background of the concept, ABB Production Cell, meets the increasing demands from manufacturing industries throughout the world to simplify through standardization and by that reduce investment cost and operating cost throughout the entire lifecycle of the production cell.

    ABB is delivering the production cell as one easy to order, use, and maintain. The production cell is developed for virtual versions and full scale production cells. The different modules shall be utilized and presented in RobotStudio and configured in Automation Builder. With generic templates and hardware it provides e.g. early visualization, standardized systems, shortened design/development phase, and enable virtual FAT(Factory Acceptance Test).

    There is multiple ways of doing a virtual commissioning and it’s a known approach for testing software and hardware together. The method used in this project is known as SIL (Software-In-The-Loop).  This means that the hardware runs as software- e.g. PLC, Drives and HMI- with same properties and behavior as the real hardware.

    This thesis focus on describing phases of an automation system and see how different phases are affected by a virtual commissioning. Benefits will be described and the existing software will be evaluated. Furthermore, an attempt of virtual commissioning has been done with focus on connecting the software for stable communication with the virtual PLC and make a PLC-task with a handshake to the robot controller and the virtual environment. The system is tested in a virtual environment with vFAT and then on the workshop (FAT). This was done to see if the softwares replicated the same behavior as the hardwares. 

    The result for the virtual commissioning is that it is possible to run the virtual PLC (VAC500) with the same time interface, behavior, and signals as the real PLC (AC500).

  • 15.
    Pedersen, Per
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Magnetisk separering av malmpebbles i KA3 - mekaniska konceptförslag: Magnetic separation of ore in KA3 - conceptual design propositions2014Independent thesis Basic level (university diploma), 180 HE creditsStudent thesis
    Abstract [en]

    This has been a thesis work for an bachelor degree at Umeå university. The work has been done at LKAB’s facilities in Kiruna and its main purpose has been to investigate and construct some conceptual designs for replacing a screen with magnetic separation in KA3 concentrator plant. First all information available about magnetic separation was gathered and studies of magnetic separation at the sorting plant and studies of the plant KA3 was conducted. Companies that manufacture magnetic separators were contacted. All information gathered has led to a decision to focus the project into dry separation because it’s the most suitable type of separation. After the information gathering phase in the project the conditions for a magnetic separator was evaluated and some measurements were taken in KA3 to make sure all the measurements for a CAD model was available. Drawings from Metso were collected to. Then the conceptual designs was drawn in CAD and evaluated with personnel from process and maintenance department. The evaluation made it possible to arrange the concepts in order of possible function which is the result from this project. It has been done in the result and conclusion part of this report. Some general thoughts about the concepts were collected and added to the report as well. The results from the project is that two of the drawn concepts are good depending on who you talk to. One concept is better then the other because its more functional and it is easier to install and it doesn’t require any new construction.

  • 16.
    Puga, Ulises
    Umeå University, Faculty of Science and Technology, Umeå Institute of Technology.
    Transportrack: Förpackning av gripklor för transport2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Cranab AB specielliserar sig på att bygga kranar och gripklor till skogsmakiner, denna rapport kommer enbart att handla om hur författaren har gått till väga för att hjälpa Cranab AB att komma med idéer och koncept för transportrack som ska transportera gripklorna som skärs ut och svetsas ihop på cranab 2 och sedan skickas över till cranab 1 för vidare bearbetning, målning och slutligen montering.

    Just nu så skickas färdiga klor av olika storlekar från cranab 2 till cranab 1 på standard SJ-pallar gjord av trä. Syftet med detta arbete är då att komma med idéer och koncept på emballage så att man kan skicka dessa gripklor i färdiga set, bestående av; innerklo, ytterklo och vagga i ett och samma ”paket”, detta för att bli av med träpallarna och effektivisera arbetet, i och med att Cranab vill kunna hantera beställningar som är både personliga och flexibla.

    För att arbeta med problemställningen så har Solid Works tagits till som hjälpmedel och även samtal med konstruktörerna samt en förstudie på Cranab AB logistic.

  • 17.
    Ugarte, Orlando
    et al.
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506-6106, USA.
    Bychkov, Vitaly
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Sadek, Jad
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506-6106, USA.
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Center for Combustion Energy, Tsinghua University, Beijing, China.
    Akkerman, V’yacheslav
    Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506-6106, USA.
    Critical role of blockage ratio for flame acceleration in channels with tightly spaced obstacles2016In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 28, no 9, 093602Article in journal (Refereed)
    Abstract [en]

    A conceptually laminar mechanism of extremely fast flame acceleration in obstructed channels, identified by Bychkov et al. ["Physical mechanism of ultrafast flame acceleration," Phys. Rev. Lett. 101, 164501 (2008)], is further studied by means of analytical endeavors and computational simulations of compressible hydrodynamic and combustion equations. Specifically, it is shown how the obstacles length, distance between the obstacles, channel width, and thermal boundary conditions at the walls modify flamepropagation through a comb-shaped array of parallel thin obstacles. Adiabatic and isothermal (cold and preheated) side walls are considered, obtaining minor difference between these cases, which opposes the unobstructed channel case, where adiabatic and isothermal walls provide qualitatively different regimes offlame propagation. Variations of the obstructed channel width also provide a minor influence on flamepropagation, justifying a scale-invariant nature of this acceleration mechanism. In contrast, the spacing between obstacles has a significant role, although it is weaker than that of the blockage ratio (defined as the fraction of the channel blocked by obstacles), which is the key parameter of the problem. Evolution of the burning velocity and the dependence of the flame acceleration rate on the blockage ratio are quantified. The critical blockage ratio, providing the limitations for the acceleration mechanism in channels with comb-shaped obstacles array, is found analytically and numerically, with good agreement between both approaches. Additionally, this comb-shaped obstacles-driven acceleration is compared to finger flameacceleration and to that produced by wall friction.

  • 18.
    Ugarte, Orlando
    et al.
    West Virginia University, USA.
    Demir, Sinan
    West Virginia University, USA.
    Demirgok, Berk
    West Virginia University, USA.
    Akkerman, Vyacheslav
    West Virginia University, USA.
    Bychkov, Vitaly
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Valiev, Damir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Effect of wall boundary conditions on flame propagation in Microchambers2015In: American Society of Mechanical Engineers, Power Division (Publication) POWER, American Society of Mechanical Engineers (ASME) , 2015Conference paper (Refereed)
    Abstract [en]

    Flame dynamics in micro-pipes have been observed to be strongly affected by the wall boundary conditions. In this respect, two mechanisms of flame acceleration are related to the momentum transferred in these regions: 1) that associated with flame stretching produced by wall friction forces; and 2) when obstacles are placed at the walls, as a result of the delayed burning occurring between them, a jet-flow is formed, intensively promoting the flame spreading. Wall thermal conditions have usually been neglected, thus restricting the cases to adiabatic wall conditions. In contrast, in the present work, the effect of the boundary conditions on the flame propagation dynamics is investigated, computationally, with the effect of wall heat losses included in the consideration. In addition, the powerful flame acceleration attained in obstructed pipes is studied in relation to the obstacle size, which determines how different this mechanism is from the wall friction. A parametric study of two-dimensional (2D) channels and cylindrical tubes, of various radiuses, with one end open is performed. The walls are subjected to slip and non-slip, adiabatic and constant temperature conditions, with different fuel mixtures described by varying the thermal expansion coefficients. Results demonstrate that higher wall temperatures promote slower propagation as they reduce the thermal expansion rate, as a result of the post-cooling of the burn matter. In turn, smaller obstacle sizes generate weaker flame acceleration, although the mechanism is noticed to be stronger than the wall friction-driven, even for the smaller sizes considered.

  • 19.
    Valiev, Damir
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Gruber, Andrea
    SINTEF Energy Research, Trondheim, Norway.
    Law, Chung K.
    Princeton University, Princeton, USA.
    Chen, Jacqueline H.
    Sandia National Laboratories, Livermore, CA, USA.
    Numerical study of interaction between Darrieus-Landau instability and spatially periodic shear flow2015In: 25th International Colloquium on the Dynamics of Explosions and Reactive Systems / [ed] M.I. Radulescu, 2015Conference paper (Refereed)
  • 20.
    Valiev, Damir
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Law, Chung K.
    Princeton University, USA.
    Chen, Jacqueline H.
    Sandia National Laboratories, Livermore, USA.
    Turbulence-affected Darrieus-Landau instability2013In: 8th US National Combustion Meeting, Western States Section/Combustion Institute , 2013, Vol. 1, 907-912 p.Conference paper (Refereed)
    Abstract [en]

    The present work studies the combined effects of weak turbulence and intrinsic flamefront hydrodynamic (Darrieus-Landau, DL) instability on the dynamics of premixed flames. Recent modeling [A. Gruber, J.H. Chen, D. Valiev, C.K. Law, J. Fluid Mech. 709 (2012) pp. 516-542] showed that DL instability contributes to the flashback of premixed hydrogen-air flames in the boundary layer of a turbulent channel flow. A concept of a turbulence-induced DL cutoff as a function of the laminar DL cutoff and the turbulence intensity was introduced for high turbulence intensities [S. Chaudhuri, V. Akkerman, C.K. Law, Phys. Rev. E 84 (2011) art. no. 026322]. It was shown qualitatively that increasing turbulence intensity limits the instability development to large scales, thereby moderating the entire effect of the instability. In order to investigate the low turbulence intensity limit in greater detail, an initially planar flame is subjected to oncoming turbulence in direct numerical simulations (DNS) with detailed hydrogen/air chemistry. A parametric study is performed by varying the turbulence intensities and the length scale of the domain. By examining the flame front shape and velocity evolution it is found that for certain ranges of turbulence intensity, the development of the DL instability is significantly affected by turbulence. It is shown that the DL instability of the flame front that is stable in the laminar case may be triggered by weak turbulence.

  • 21.
    Valiev, Damir
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Qu, Zhechao
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Steinvall, Erik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Schmidt, Florian
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Measurement and simulation of atomic potassium in the plume above potassium hydroxide in a methane-air flat flame2016Conference paper (Other academic)
  • 22.
    Valiev, Damir
    et al.
    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544-5263, USA.
    Zhu, Manqi
    Computational Fluid Dynamics Team, CERFACS, Toulouse 31057, France.
    Bansal, Gaurav
    Intel Corporation, Hillsboro, OR 97124, USA.
    Kolla, Hemanth
    Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA.
    Law, Chung K.
    Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544-5263, USA.
    Chen, Jacqueline H.
    Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550, USA.
    Pulsating instability of externally forced premixed counterflow flame2013In: Combustion and Flame, ISSN 0010-2180, E-ISSN 1556-2921, Vol. 160, no 2, 285-294 p.Article in journal (Refereed)
    Abstract [en]

    The diffusive-thermal pulsating instability of Le > 1 flames can considerably alter global quantities such as the flammability limit and mass burning rate, making its study practically relevant. In the present study we investigate the behavior of pulsating flames in unsteady flow fields using one-dimensional and two-dimensional flame simulations of laminar premixed rich hydrogen/air flame in a counterflow configuration, focusing on the response of the flame to imposed fluctuations in strain rate and equivalence ratio. These effects become important when the flame propagates in an unsteady flow field, for example, in turbulent flows. In the case of strain rate forcing, the flame is found to undergo oscillatory extinction if the forcing frequency is less than the pulsation frequency. For strain rate forcing frequencies higher than the pulsation frequency, the flame is found to be largely unresponsive to the upstream flow velocity fluctuations. The parametric study for equivalence ratio forcing shows that the pulsating instability is promoted with increasing inlet velocity, increasing amplitude and mean value of the imposed composition fluctuation. At the same time, it is observed that increasing the frequency of the imposed oscillations may attenuate the pulsating instability. Moreover, it is found that a flame subjected to pulsating extinction may be able to sustain pulsating combustion if forced with high-frequency inlet composition variation. Based on the insights gained from one-dimensional simulations, two-dimensional simulations of these pulsating flames are performed to provide additional insights on the shape and location of cells and cusp formation in these flames.

  • 23.
    Welander, Simon
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Serviceförbättringar av GTC-200MSS2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Som ett sista arbete på högskoleingenjörsutbildningen i maskinteknik på Umeå universitet så har jag sett över servicevänligheten på ett reservkraftsaggregat. Attacus Power AB har stått som värd för detta arbete och även tillhandahållit arbetsplats under utförandet.

    Ett reservkraftsaggregat är ofta en dieseldriven motor kopplad till en generator som alstrar ström. Denna ström kan sedan användas för att driva sjukhus eller liknande vid ett eventuellt strömavbrott.

    Modellen som skulle ses över heter GTC-200MSS och den är en extra tyst modell avsedd för platser som filminspelningar och liknande där ljudnivån är en viktig faktor.

    Det jag skulle utföra var att försöka hitta en lösning där motor och generator, med så litet ingrepp som möjligt, kunde tas ut för underhåll.

    Arbetet började med att olika lösningsförslag togs fram. Allt från att vicka av hela höljet, till en ny utformning av modellen. Efter att alla förslag presenterats och gåtts igenom med inblandade på företaget, så beslutades att en lösning där en truck eller liknande med hjälp av sina gafflar kunna lyfta ut motor och generator var den bästa lösningen.

    För att göra det enkelt för de som skulle utföra ingreppet så gjordes en enkel manual.

    En modell togs fram där truckens gafflar legat till grund för utförandet samt dess belastningsfall. Genom att lägga till en enkel dropplåt under motor och generator ökas trivsamheten för de som ska arbeta med maskinen efter ett par år då maskinen blir lättare att hålla ren.

    För att inte bygga för mycket på höjden beslutades att göra dörren så stor som det gick och sedan även sänka dörren så att den nedre dörrkarmen inte skulle bli ett hinder för gafflarna.

    En FEM-analys gjordes för att se om konstruktionen skulle klara av de olika belastningsfallen. Det visade sig att så inte var fallet utan en förstärkning var ett måste.

    Elskåpet placerades om för att inte vara i vägen för den högre generatorplaceringen. Detta var inte optimalt då installationen kommer försvåras eftersom väggen som den nu ska fästas på installeras sist med höljet.

    Om denna rapport skulle göras om, så skulle större vikt läggas på att se om generatordörren kunnat användas som en lösning. Detta skulle medföra fördelar som att elskåpet inte skulle behöva flyttas samt att tyngdpunkt av generatorn och motorn skulle hamna närmare trucken vid ett lyft.

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