In many technical applications chemical reactions are used. One of these is a so called decolorization, in which an ion exchange resin is used to remove a dye from water. To apply this decolorization technique a Rotating Bed Reactor, or RBR for short, can be used. It is filled with the ion exchange resin and spun inside the water. Whilst spinning, the reactor percolates the water, letting it interact with the ion exchange resin and thus removing the dye. This project aims to use Computational Fluid Dynamics (CFD) as a tool to create a model for the decolorization process when a RBR is used. The goal is to achieve a reaction model for the process that can be applied to various RBR models, i.e. scaled, to aid for example product development and research. A decolorization process in which methylene blue is removed from deionized water using a SpinChem S2 RBR inside a V2 vessel, using a NRW 1160 ion exchange resin, is investigated. Experiments are conducted where the concentration of methylene blue in deionized water is measured during the decolorization process using a transmittance probe. From the experimental results a linear regression model is fitted to achieve a model for the reaction's rate constant, determining its reaction rate, depending on the fluid velocity inside the RBR and the temperature of the fluid. CFD is used to find the flow field for different rotational speeds of the RBR inside the vessel. Using the steady-state flow field species transport simulations are done using the created reaction model. This is done to compare numerical simulations to experimental results. The results show that the created reaction model can predict the time taken to absorb the methylene blue onto the ion exchange resin. Deviations from the exact decay rate of methylene blue concentration is seen, and are concluded to come from conversion of global reaction rate in the vessel to local reaction rate inside the RBR. The reaction model has not been tested explicitly on other types of RBR, thus nothing can be said about its performance. However, care has been taken to not include any RBR geometry dependent parameters in the model.

This study was performed to investigate aerodynamic characteristics of the 37.5% scaled­ down Green Raven MK18 airframe, to evaluate boundary corrections method, and to investigate on support interference. A wind tunnel test was originally planned on June 2021 at a Large­Low­Speed Wind Tunnel at University of Bristol; however, due to COVID­19 travel restrictions, the test has been postponed to November 2021. In or­der to supplement the work and data directly required for the test, computational fluid dynamics (CFD) investigations were performed in free air and in wind tunnel condi­tions, both with and without support interference, at a Reynolds number of 7E+05. The simulations utilized an incompressible Reynolds-­Averaged­-Navier.­Stokes equa­tion accompanied with k − ω SST for turbulent modelling. Corrections factors were obtained to compensate for wall interference, and results indicate a satisfactory agree­ment between free ­air and wind­ tunnel corrected data for wall interference. The sup­ port structure interferes with the aerodynamic loads produced by the model. Lift and drag decrease, and pitching moment increases compared to WT without support structure condition. / Denna studie utfördes för att undersöka aerodynamiska egenskaper hos det nedskalade Green Raven MK18­flygplanet för 37.5%, för att utvärdera gränskorrigeringsmetoden och för att undersöka stödinterferens. Ett vindtunneltest planerades ursprungligen i juni 2021 vid en stor­låghastighets vindtunnel vid University of Bristol. Men på grund av resebegränsningar för covid­19 har testet skjutits upp till november 2021. För att komplettera det arbete och de data som direkt krävs för testet, utfördes CFD under­ sökningar (Computational Fluid Dynamics) i fri luft och i vindtunnelförhållanden, både med och utan supportinterferens, med ett Reynolds­tal på 7E+05. Simuleringarna använde en inkompressibel Reynolds­Averaged­Navier­Stokes­ekvation tillsammans med k − ω SST för turbulent modellering. Korrigeringsfaktorer erhölls för att kom­ pensera för väggstörningar, och resultaten tyder på en tillfredsställande överensstäm­ melse mellan frilufts­ och vindtunnelkorrigerade data för väggstörningar. Stödstruk­ turen stör de aerodynamiska belastningar som modellen producerar. Lyft och drag minskar och stigningsmomentet ökar jämfört med WT utan stödstruktur.

Scania works continuously to develop internal combustion engines and after treatment systems which can achieve low pollutant emissions and high efficiency. A major principal that Scania adopted for this goal is the Simulation Driven Development (SDD) process. Here computer aided simulations aid to develop designs and improve characteristics all the while reducing the iterative prototyping and testing process. Currently, parametric modelling and Design of Experiments (DoE) is a proven and major mode of exploring designs within the various stakeholder fields of development; namely structural, fluid mechanics and acoustics.  Topology optimisation in fluid flow is a new field which promises quick exploration of design spaces. The result of topology optimisation are unintuitive designs that could serve as baseline designs which can further reduce the design process. The objective of the thesis was to explore topology optimisation and investigate a way to incorporate topology optimisation in the design process at Scania CV AB. For this task Tosca Fluid by Dassault Systèmes was chosen for its optimisation capabilities, which uses back-flow as the criteria of optimisation. The case study was conducted based on the MTX diesel one box inlet end-plate which was used as reference. The dimensional constraints of the reference product were used to model and utilise the developed workflow. Since this task involved the use of substrates for exhaust gas filtration, it was imperative to explore uniformity of flow over the substrate as an additional optimisation criterion. The project studied modelling design spaces to satisfy the design criteria and the shortcoming the software currently poses have been documented in this report. The report also mentions the tasks involved in setting up simulation cases to work well with Tosca Fluid. In the current stage of the thesis work it was not possible to incorporate uniformity as an additional criterion and hence fails in using Tosca Fluid to optimise topology for turn volumes involving the use of substrates. / Scania arbetar kontinuerligt med att utveckla förbränningsmotorer och efterbehandlings system som kan uppnå låga föroreningar och hög effektivitet. En viktig princip som Scania antog för detta mål är processen Simulation Driven Development (SDD). Här hjälper datorstödda simuleringar att utveckla mönster och förbättra egenskaper samtidigt som den iterativa prototyp- och testprocessen reduceras. För närvarande är parametrisk modellering och Design of Experiments (DoE) ett beprövat och viktigt sätt att utforska konstruktioner inom de olika intressenternas utvecklingsområden; nämligen konstruktion, fluidmekanik och akustik. Topologioptimering i vätskeflöde är ett nytt område som lovar snabb utforskning av designutrymmen. Resultatet av topologioptimering är icke-intuitiva konstruktioner som kan fungera som baslinjedesigner som ytterligare kan minska designprocessen. Syftet med avhandlingen var att utforska topologioptimering och undersöka ett sätt att integrera topologioptimering i designprocessen på Scania CV AB. För denna uppgift valdes Tosca Fluid av Dassault Systèmes för sina optimeringsmöjligheter, som använder återflöddet som kriterier för optimering. Fallstudien genomfördes baserat på MTX diesel först låda inloppsändplatta som användes som referens. Referensproduktens dimensionella begränsningar användes för att modellera och använda det utvecklade arbetsflödet. Eftersom denna uppgift innebar användning av substrat för avgas filtrering, var det absolut nödvändigt att undersöka flödets enhetlighet som ett ytterligare optimerings kriterium. Projektet studerade modellerings designutrymmen för att uppfylla design kriterierna och den brist programvaran för närvarande har dokumenterats i denna rapport. Rapporten nämner också de uppgifter som är involverade i att skapa simuleringsfall för att fungera bra med Tosca Fluid. I det aktuella skedet av avhandlings arbetet var det inte möjligt att införliva enhetlighet som ett ytterligare kriterium och misslyckas därför med att använda Tosca Fluid för att optimera topologi för sväng volymer som involverar användning av substrat.

Volvo Car Corporation (VCC) uses Computational Fluid Dynamics (CFD) and wind tunnel during the aerodynamic development of new vehicles. In the past VCC main focus has been on the drag force correlation to the wind tunnel measurements but in recent years improved methods for lift force correlations has been highly wanted. Three objectives were considered in this study to improve the lift force correlation between the CFD simulations and wind tunnel measurements for geometrical configurations of the V60 and S60 models.Poor mesh resolution for the wall bounded flow existed for the VCC mesh method and therefore prisms layers were considered in this thesis to increase the mesh resolution inside the boundary layer.As slick tyres generally were used in the CFD simulations better geometrical correlation was wanted to be studied as it could improve the lift force correlation between CFD simulations and wind tunnel measurements. Therefore detailed tyres were considered in this study.As the coarsest surface mesh size was used for the underbody and the components inside the engine bay, where some of the highest flow velocities occurred, mesh refinements were investigated for engine bay and underbody in this study.The prisms layers improved the predicted behavior for the boundary layer as it captured the large velocity gradients more accurately. Due to this, the skin friction prediction was also improved. Different flow behavior around the front wheels and rear wake occurred due to earlier separation. The different flow field caused an improved correlation for the lift force but worsened correlation for the drag force due to increased pressure at the rear of the cars. However, the front lift force trend correlation for the considered configurations was improved with the prisms layer mesh method.The detailed tyres caused slight more disturbances for the underbody flow which caused more attached flow around the rear of the car hence lowered pressure. Earlier separation around the front wheels also occurred for the detailed tyre geometry as the disturbed flow around the wheels was increased. Slight improved correlation for the front and rear lift forces to the wind tunnel measurements could be seen with the detailed tyre compared to the slick tyre.The mesh refinements for the engine bay and underbody showed significant differences for the flow at the underbody which had significant impact on the flow at the rear wake for the V60 model. Minor differences could be seen for the aerodynamic forces for the baseline configuration for the V60 model while great differences occurred for the configurations affecting the underbody. Due to this significant improved correlation for the front and rear lift force trends were achieved for the underbody configurations with the refined engine bay and underbody mesh method.Conclusions could be drawn that the prisms layer caused earlier separation due to its increased mesh resolution for the wall bounded flow. However, finer mesh resolution was needed inside the boundary layer to ensure consistent separation behavior for both the considered models. Improved correlation for the front lift force could however be seen. The detailed tyre only had minor effects on the flow field and aerodynamic forces and therefore not so important to include for further studies. The refined engine bay and underbody caused significant improved lift force trend correlation to the wind tunnel measurements and should be considered for future studies. To improve the correlation between CFD simulations and wind tunnel measurements increased mesh resolution for the wall bounded flow should be considered to better capture the large velocity gradients close to the wall.

abstract: This study uses Computational Fluid Dynamics (CFD) modeling to analyze the dependence of wind power potential and turbulence intensity on aerodynamic design of a special type of building with a nuzzle-like gap at its rooftop. Numerical simulations using ANSYS Fluent are carried out to quantify the above-mentioned dependency due to three major geometric parameters of the building: (i) the height of the building, (ii) the depth of the roof-top gap, and (iii) the width of the roof-top gap. The height of the building is varied from 8 m to 24 m. Likewise, the gap depth is varied from 3 m to 5 m and the gap width from 2 m to 4 m. The aim of this entire research is to relate these geometric parameters of the building to the maximum value and the spatial pattern of wind power potential across the roof-top gap. These outcomes help guide the design of the roof-top geometry for wind power applications and determine the ideal position for mounting a micro wind turbine. From these outcomes, it is suggested that the wind power potential is greatly affected by the increasing gap width or gap depth. It, however, remains insensitive to the increasing building height, unlike turbulence intensity which increases with increasing building height. After performing a set of simulations with varying building geometry to quantify the wind power potential before the installation of a turbine, another set of simulations is conducted by installing a static turbine within the roof-top gap. The results from the latter are used to further adjust the estimate of wind power potential. Recommendations are made for future applications based on the findings from the numerical simulations. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2017

Sebastian Zetterström, Master of Science in energy systems, Mälardalens University in Västerås. Abstract of Master’s thesis, submitted 16th of August. Evaluation of a suction pyrometer by heat and mass transfer methods. The aim of the thesis is to evaluate the cooling of a specific suction pyrometer which is designed by Jan Skvaril, doctorate at Mälardalens University. First part is explained how the balances and correlations are performed before being implemented in MATLAB, after this  a ANSYS Fluent model is constructed and explained, which is used for the comparison of results. The cooling is performed by using water at an inlet temperature of 10°C and an assumed flue gas temperature of 810°C. Sensitivity analysis are performed to test the stability of the models which yield good results for stability, done by adjusting both flue gas temperature and inlet cooling water temperature which are as well presented for observation. From doing further MATLAB sensitivity analysis which show that the model still performs well and is stable. The resulting cooling water is heated to approximately 24, 8°C and the flue gas is cooled to 22, 4°C, in ANSYS Fluent the answer differs approximately 2°C and results in 20, 4°C which can be considered by looking at the flue gas inlet temperature of 810°C that this can be deemed an insignificant change and can therefore conclude that the comparison between the two platforms match each other good and that calculations can be considered accurate. Keywords:  Suction pyrometer, cooling, heat transfer, thermal resistance network, MATLAB, ANSYS Fluent, simulation

Uppsala University wants to make a wave tank which can be used for experiment and education purpose. The project's aim is to get design parameters required to make a wave tank, design the wave tank, to do analysis on wave parameters taken from results and analysis of material which can be used to construct it.  This project is an extension of the project called Numerical Wave Tank Design in which a literature study on existing wave research facilities was done [1]. The data from this project is used to get the dimensions of the wave tank. A study on hydrodynamics and wave theory is done to understand flow motion and wave generation.   Ansys Fluent is used for Computational Fluid Dynamics (CFD). The software is used to test the wave tank with different wave absorber and observe if a good quality wave with a minimal reflection can be generated in the wave tank of chosen dimensions. Four models were created for testing wave absorber of different shapes. The setup for all the models was kept the same for comparison purposes. Waves generated from CFD were later compared with the theoretical waves obtained from wave theory. The next part was to model the wave tank in Computer-Aided Design (CAD) software, SolidWorks. The stress and strain analysis was done on the walls and support beam of the wave tank to know if the structure can sustain the water when fully filled. After creating static simulation different scenarios were performed on the beam and stand of the wave tank. The design study on these parts was compared to see which case provides a more optimal solution. It was found out that wave absorber having an elevation of 18.4 degrees, i.e., 1:3 slope provides the highest wave height for the given parameter and dimensions of the wave tank. In wave analysis, it was seen that wave height is proportional to the stroke length, water depth is proportional to wave height and time period is inversely proportional to the wave height. Cast stainless steel is used in a wave tank as it is cheap, reliable and robust. It was found out that the support beam 0.015 m thick is enough, although it can be increased to 0.02 m. In the design study of the wave tank stand, it was found out that a leg distance of 0.78 m and a leg width of 0.06 m is sufficient to withstand the weight of the wave tank.

For each generation of electronic equipment there is a trend towards higher power den-sities. Increased heat generation is an undesired consequence that the thermal design unit in a company must handle. The goal of thermal design engineer/unit is to utilizethe same volume to more efficiently transfer more heat from the equipment. This can bedone by exploring more complex and advanced heat sink geometries, optimizing the finshapes and so on. The new prototypes developed will be tested for their reliability and endurance in special chambers called climate chambers, that simulate desired environ-ments. The measurements by thermal design teams in these kind of climate chambers are mainly of outdoor products, whose cooling is based on natural convection. Forcedcooling using fans is optional for these outdoor products. The climate chambers in general provides temperature measurement as the outputto the analysis, though there are other important parameters that define the operationalfunctionality of an equipment. The ability to visualize the flow characteristics duringthe process of testing is a valuable aid in the design process. A virtual/CFD form of thephysical climate chamber (CC) would empower the design process, while alleviating theusage of the climate chambers for such analyses. CFD offers a wide range of capabilitiesthat lets the user change the boundary conditions with great ease compared to that ofthe experimental setup. The numerical model developed in this thesis project provides results, that help inunderstanding the physics involved in fluid flow inside the physical climate chamber.Turbulence quantification of the flow is the main aim of this thesis project, which wouldbe resourceful in future works. Experiments are conducted inside the climate chamber, in order to aid the construction of numerical model as well as serve as source of vali-dation for the numerical results. Laminar transient case simulations are preferred over use of any turbulence models, to limit any kind of predictions made by these turbulencemodels. Integral length scales and turbulence intensities are compared and reason fordiscrepancies are addressed. The results from the comparisons show that, the numerical model emulates physicsof actual flow inside the climate chamber. However, there are many factors that directlyaffect the results, making it difficult to precisely quantify the error, within the time periodof this thesis project.

This work is focused on lithium-ion batteries in general and their modeling capabilities in ANSYS Fluent. The various advantages and disadvantages of li-ion batteries are describes in my work. There are also described the various models and submodels offered by ANSYS Fluent. An essential part of the work is to model the real battery and compare the results between the real battery and the simulation itself. Finally, simulation of battery breakdown is performed.

The main aim of this paper are models of Li-Ion storage batteries made and simulated in ANSYS Fluent software. Various ways of simulations are discussed with main aim on ECM method and how its numerical model is computed. A process of getting information and required data from real battery to be compared with simulation results by EIS method is also discussed. These results are then compared with results from ANSYS Fluent.