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The World Health Organization estimates that over two billion people did not have access to a toilet in 2017. The dejects produced often end up in bodies of water and, as one in every ten crops is watered with wastewater, this is estimated to cause half a billion deaths per year. There are currently many initiatives to reach this sanitation Global Goal, including those from people such as Bill Gates and projects such as The Solar Project. The Solar Project is based in South Africa and is based on cooperation between various companies which provides them with the different components for the installation of Resource Centers, that produce fertilizers of human waste. One of the components of these Resource centers are dry-toilets, which are provided by SUPERFUNKYFUTURE. This thesis is about an analysis of a toilet model and building a function tree, performing a 2D Volume of Fluid simulation on it to see even more critical geometries. Each one of those geometries had one alteration designed. These alterations were also combined into different models and they were all tested in both 2D and 3D simulations. The results from the simulations were then post-processed in CFD-Post and animated, to allow the qualitative analysis to be performed through a Pugh Matrix and decide between designs to recommend an improved internal geometry to SUPERFUNKYFUTURE. / Världshälsoorganisationen, WHO, beräknar att mer än två miljarder människor inte hade tillgång till toaletter 2017. Avföringen från dessa människor hamnade ofta i sjöar och floder och det vattnet användes sedan i sin tur för bevattning av grödor. Detta beräknas vara orsaken till en halv miljard dödsfall per år. Det finns för tillfället många initiativ att uppnå det globala målet för rent vatten och sanitet för alla, däribland arbetar Bill Gates och projekt så som “Solar Project”. “Solar Project” har sin bas i Sydafrika och är ett samarbete mellan flera företag som tillhandahåller olika komponenter som krävs för att skapa resurscenter, som kan användas för att producera gödsel av mänsklig avföring. En av komponenterna för dessa resurscenter är torrtoaletter som är försedda av SUPERFUNKYFUTURE. Denna tes handlar om att analysera en toalettmodell, bygga ett funktionsträd, utföra en 2D “Volume of Fluid”-simulering för att upptäcka kritiska geometrier. Varje sådan geometri fick en ändring designad. Dessa förändringar kombinerades till olika modeller som sedan blev testade med både 2D- och 3D-simuleringar. Resultaten från simuleringarna blev sedan bearbetade i CFD-Post och blev animerade, detta för att möjliggöra en kvalitativ analys genom en konceptviktningsmatris. Från Konceptviktningsmatrisen kunde man välja mellan designerna och rekommendera en förbättrad intern geometri till SUPERFUNKYFUTURE.

Computational Fluid Dynamics (CFD) has become one of the main instruments for the prediction of many commercial and research oriented fluid flow and heat transfer problems. While single phase flow analysis through CFD has gained grounds within the commercial industry, multiphase flow analysis is still the subject of further research and development. Heat Pipes and thermosyphones are no exception to this. However, the involvement of more than one fluid phase within these devices has made their analysis through CFD more challenging and computationally more demanding to perform. In this thesis, computational fluid dynamics is used as a modelling tool in order to predict the thermal hydraulic behaviour of multiphase environment within thermosyphones and heat pipes. Eulerian two-fluid method is used to solve the conservation equations for mass, momentum and energy, for each phase along with the inclusion of interfacial heat and mass transfer terms. Numerical predictions are obtained for the steady-state and transient operation of stationary thermosyphon, while rotating heat pipes operation is also simulated using axially and radially rotating heat pipe models. Apart from using the commercially available CFD code for the analysis of thermosyphones related simulation, numerical work is performed regarding the coupling of momentum equations based on Eulerian two-fluid modelling scheme. OPENFOAM open source code is used and modified to include the Partial Elimination Algorithm (PEA) for the coupling of interfacial exchange terms, including interfacial mass transfer term, in the momentum equations of both phases. Results obtained from above discussed studies provide good agreement with corresponding experimental and analytical observations.

There is an ongoing interest in analyzing the flow characteristics of swimming fish. Biology has resulted in some very efficient motions and formulating these motions is of interest to engineers. One such theory was written by Dr. William Vorus and Dr. Brandon Taravella involving ideal efficiency. It is therefore interesting to test the calculations to see if it is possible to design a motion that can create thrust without necessarily creating vorticity. The computational fluid dynamics software of ANSYS Fluent was used to calculate the resulting flow field of the eel motion to compare with the theoretical values.

Theoretical, numerical and experimental investigations have been successfully carried out to characterise the thermal performance of an air-to-water multi-pass heat exchanger equipped with thermosyphon technology. Air and water are the heat source and the heat sink on the evaporator and condenser, respectively. Evaporator and condenser are connected by six thermosyphons, through which thermal energy is transferred. The investigation was performed for two multi-pass configurations at various inlet conditions: a range of air inlet temperatures (100, 150, 200 and 250°C) and mass flow rates (0.05, 0.08, 0.11 and 0.14 kg/s). The water inlet conditions were kept constant (a temperature of 15°C and a mass flow rate of 0.08 kg/s). The theoretical model was built by applying the thermal resistance analogy with the aid of convection, boiling and condensation correlations found in the literature. It was found that the thermal resistances in the first pass act in parallel mode along the ones in the second pass. Similarly, in the case of three passes. Also, the external convective thermal resistance were found to be the major contributor to the overall thermal resistance in the entire heat exchanger. ANSYS Fluent was the numerical tool used to investigate the shell-side convective heat transfer for two multi-pass configurations. The CFD model has been experimentally validated. The two-phase change processes inside the thermosyphons were not modelled during the simulation. Instead, the thermosyphons were treated as solid rods with a constant thermal conductivity, which was calculated. The overall rate of heat transfer was obtained by both CFD and a theoretical model, and the results lay within 15% of the experimental data. The numerical predictions demonstrated that the K-ε Realizable turbulence model with scalable wall function is a reliable tool for predicting heat transfer and fluid flow in such types of heat exchangers. This investigation will add a great knowledge to the academia in terms of both experimentation and modelling in the area of multi-pass thermosyphons-based heat exchangers. Also, it provides the industries with a cost effect design tool for future modelling of similar heat exchanger systems.

The transition from inner to outer ballistics is a crucial part for the stability of the projectile. A projectile is mainly stabilized in two ways, with fins or by rotation. This work is limited to analyze a fin stabilized projectile. The launch of the projectile and the deployment of the fins are a quick process, therefore high forces and high temperatures will act the stability of the projectile. Due to these factors, it is hard to quantify experiments to analyze the stability of the projectile. To gain knowledge about how the forces will affect the path of the projectile during the launch and the deployment of its fins Computational Fluid Dynamics (CFD) can be a useful technique. In this work, a 2D methodology have been developed in Ansys Fluent to analyze the launch of a projectile and the deployment of the fins. A RANS model have been used in combination of dynamic mesh in order to handle the movement of the projectile. The projectile accelerates due to a pressure rise which have been initialized by a mass flow and energy curve as a source term. This work indicates that it is possible to predict the flow behavior and the forces influencing the projectile and the deploying fins. This work used a 2D model throughout the simulations and a 3D model is therefore needed to further compare and validate the simulation methodology.

The master‘s thesis is focused on issue of pumping in the experimental pumped chambre of an environmental scanning microcope. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on electron microscopy and its problem and vakuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part contains the results of gas flow in the differential pumped chambre. The problematics were solved by Ansys Fluent system.

Transpiration cooling as potential replacement of multi-hole effusion cooling for gas turbine engines combustion liner application is investigated by comparing their cooling film effectiveness based on the mass transfer analogy (CFEM). Pressure sensitive paint was used to measure CFEM over PM surfaces which was found to be on average 40% higher than multi-hole effusion cooling. High porosity PM with low resistance to flow movement were found to offer uneven distribution of exiting coolant, with large amounts leaving the trailing edge, leading to lopsided CFEM. Design of anisotropic PM based on PM properties (porosity, permeability, and inertia coefficient) were investigated using numerical models to obtain more uniform CFEM. Heat transfer analysis of different PM showed that anisotropic samples offered better thermal protection over isotropic PM for the same porosity. Comparison between cooling film effectiveness obtained from temperatures CFET against CFEM revealed large differences in the predicted protection. This is attributed to the assumptions made to apply CFEM, nonetheless, CFEM remains a good proxy to study and improve transpiration cooling. A method for creating a CAD model of designed PM is proposed based on critical characteristics of transpiration cooling for future use in 3D printing manufacturing.

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This diploma thesis focuses on optimization of the flap for the ultralight aircraft Skyleader JA 600, which is produced by the Jihlavan s.r.o. company. Individual types of flaps used in ultralight aircrafts are described in the initial phase of the thesis. In addition, description of the plane of interest Skyleader has been conducted, while along with the basic characteristics the focus is mainly on its wing and flap. The thesis continues with detailed CFD method calibration task, which is mostly focused on the basic turbulent models comparison. The optimization task conducted within this diploma thesis includes CFD calculations to determine aerodynamic characteristics of the flap provided by Jihlavan company, and subsequent determination of its optimal position. An important part of this thesis is also evaluation of the load and strength of the flap in previously determined optimal position. At the end, the strength and fly tests of the flap in the new position are described.