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1
Anderle, Milan. "Vývoj modelu kalcinace pro ANSYS Fluent". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-367526.
Testo completoAbstract (sommario):
The aim of the diploma thesis was creating a decarbonisation model of lime, implementation the model into CFD tool ANSYS Fluent and to test the decarbonisation model in a model of a real reactor. The required model was based on assumptions for a Shrinking Core Model (SCM). The main objective of this work was the non-catalytic conversion of substances and the search for the most used mathematical models for calcination. The CFD calculation, the sensitivity analysis and the Fluente parametric study were used. Data on the composition of gas flow, temperature, pressure and mass flow of limestone particles were selected for input variables. The particle model called Multiple Surface Reactions (MSR), which is a standard part of Fluent, was used at first. Subsequently, a UDF which was based on the SCM assumptions was written in the programming language C. The results of the CFD calculation were compared with the experimental values from the dissertation. It has been found that the MSR is sufficiently precise for calculation purposes but neglects the internal diffusion of CO2 through the CaO layer which forms behind the reaction front during calcination. It was found that it is possible to solve the flow with ongoing calcination without the need to know the parameters of the Arrhenian equation if the UDF is used. The created UDF incorporates the influence of intraparticular CO2 diffusion on the overall reaction rate.
2
Acharya, Rutvika. "Investigation of Differences in Ansys Solvers CFX and Fluent". Thesis, KTH, Mekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203937.
Testo completoAbstract (sommario):
This thesis aims at presenting Computational Fluid Dynamics studies conducted on an axisymmetric model of the Siemens SGT-800 burner using Ansys Fluent, Ansys CFX and Ansys ICEM. The goal is to perform a mesh study and turbulence model study for isothermal flow. The result will show the differences observed while using the two solvers by Ansys, Fluent and CFX. Two different meshes, A, coarse and B, optimal have been used for the mesh study. This will reveal the mesh dependency of the different parameters and if any differences are observed between the solver’s convergence and mesh independency performance. To further validate the mesh independency, a simplified test case is simulated for turbulent flow for 32 different cases testing the numerical algorithms and spatial discretization available in Ansys Fluent and finding the optimal method to achieve convergence and reliable results. Turbulence model study has been performed where k-ε, k-ω and k-ω Shear Stress Transport (SST) model have been simulated and the results between solvers and models are compared to see if the solvers’ way of handling the different models varies.Studies from this thesis suggest that both solvers implement the turbulence models differently. Out of the three models compared, k-ω SST is the model with least differences between solvers. The solution looks alike and therefore it could be suggested to use this model, whenever possible, for future studies when both solvers are used. For the models k-ε and k-ω significant differences were found between the two solvers when comparing velocity, pressure and turbulence kinetic energy. Different reasons for its occurrence are discussed in the thesis and also attempts have been made to rule out few of the reasons to narrow down the possible causes. One of the goals of the thesis was to also discuss the differences in user-interface and solver capabilities which have been presented in the conclusions and discussions section of the report. Questions that still remain unanswered after the thesis are why these differences are present between solvers and which of the solvers’ results are more reliable when these differences have been found.
3
Longo, Joel Joseph. "Unsteady Turbomachinery Flow Simulation With Unstructured Grids Using ANSYS Fluent". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376875053.
Testo completo
4
Šimík, Marcel. "Specifika nastavení řešiče v systému Ansys Fluent pro nízké tlaky v EREM". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-319633.
Testo completoAbstract (sommario):
This thesis is focused on electron microscopy which issue is discussed at the beginning of work. The main attention is dedicated to the Environmental electron microscope, especially the differentially pumped chamber, which the thesis deals with. There is a production of an experimental chamber for analysis of shock waves on going therefore main goal of this thesis was to analyze the flow pattern in this chamber. Using the Ansys Fluent program, simulations of the characteristic flow that arises from the pumping of the vacuum chambers namely the ultrasonic flow at low pressures on which the most suitable turbulent module was applied as well as the degree of discretization was performed. The final analysis of this flow pattern is primarily focused on the localization of the shock wave which experimental evidence is to be lodged by shadow optical method as a part of the new concept of the chamber. The basis for the simulation of the chamber was taken over by Dr. Danilatos, with which the results were compared.
5
Soueidan, Ahmed Yassin. "A NEW PEMFC FLOW FIELD PLATE OPTIMIZATION COMPARISON - ANSYS FLUENT FUEL-CELL SIMULATION". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/908.
Testo completoAbstract (sommario):
The performance of a new cathode flow field plate located on a PEM fuel cell was compared to an industry standard and optimal serpentine design provided from literature. Results were successfully collected through a fuel cell module integrated with the 3D computational fluid dynamics package ANSYS Fluent. Contour plots showing a cathode catalyst layer comparison of local current density, oxygen molar concentrations, water content, and the pressure inside of the flow channels were compared with both PEM fuel cell configurations. The new flow field plate/pattern was shown to distribute more mass species of oxygen, more evenly, to the reaction site given the same boundary conditions, thus contributing to more ideal local current density. The net-power was determined for both fuel cells which included the pump work-in and power-out from each fuel cell. The new flow field plate was shown, through computational power performance results, to outperform the conventional flow pattern by up to 2.4% when excluding the effects of pump work, and still upheld a positive gain when factoring in this value. With an additional 18 corners for improved water management due to the effects of wall adhesion, the new bipolar plate was proven to become a new competitor in PEM fuel cell technology. Furthermore, this thesis gives further insight on PEMFC digital prototyping.
6
CARO, DIAZ FREDDY SANTIAGO. "ANALYSIS OF FLUID STRUCTURE-INTERACTION (FSI) PROBLEMS IN ANSYS". Thesis, Faculty of Engineering and Information Technologies. School of Aerospace, Mechanical & Mechatronic Engineering, 2015. https://hdl.handle.net/2123/30023.
Testo completoAbstract (sommario):
The Fluid-Structure Interaction problems occur in many natural phenomena and man-made engineering systems, this fact has promoted the research in this area. The research in this field of study is implementing two different methodologies. The first one is the use of commercial programs that have developed FSI capabilities such as Ansys or ADINA. The second methodology is the development of computational codes to solve specific problems of FSI analysis. This Project in particular focuses in the evaluation of Ansys-Fluent to perform FSI simulations. Two aeroelastic cases were simulated in Ansys, they were: the delta wing, and the Onera M6 wing. The delta wing simulation is subsonic and its structure is a simple flat plate made out of aluminum. The Onera M6 wing simulation is transonic and its structure has multiple components that are made out of an orthotropic material. The FSI simulations of the delta wing were validated through comparison with experimental data reported in literature. A turbulence analysis and a mesh independence analysis were carried out as well. The validation showed a limited capability to replicate the results that were obtained in the experiment. The FSI simulations of the Onera M6 wing were validated through comparison with a simulation that was carried out in Patran-Nastran. In addition, a computational fluid dynamics (CFD) simulation in steady state was performed in Ansys in order to establish the bases of the configuration that was implemented in the FSI simulations in Ansys. The validation showed that Ansys-Fluent is able to reproduce the results obtained in Patran-Nastran.
7
Origuella, Daniele. "ANSYS Fluent usage in product development : Aqualitative analysis of Volume of Fluidsimulations in the internal design of a dry toilet". Thesis, KTH, Hållbar produktionsutveckling (ML), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298067.
Testo completoAbstract (sommario):
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.
8
LOPEZ, REBOLLAR BORIS MIGUEL 547458, e REBOLLAR BORIS MIGUEL LOPEZ. "Aplicación de cfd-ansys-fluent en el estudio hidrodinámico de tanques de recirculación empleados en acuacultura". Tesis de maestría, CENTRO INTERAMERICANO DE RECURSOS DEL AGUA - Universidad Autónoma del Estado de México, 2015. http://hdl.handle.net/20.500.11799/40428.
Testo completoAbstract (sommario):
Tesis que se presenta para obtener el grado de maestría en Ciencias del AguaLa Dinámica de Fluidos Computacional (CFD) tiene distintas aplicaciones en diversas áreas de la ingeniería, principalmente en la modelación de flujos, donde es utilizada para conocer las características de un flujo en movimiento y determinar las variables que intervienen en su comportamiento, de manera teórica pero económica y con resultados muy cercanos a la realidad. En acuacultura, la CFD es utilizada para visualizar y evaluar el comportamiento hidrodinámico de tanques de cultivo de peces, tomando en cuenta las condiciones de flujo para el sano desarrollo de los peces. Sin embargo, pocos trabajos analizan la eficiencia de remoción de sedimentos de forma natural, considerando el comportamiento del flujo dentro del tanque. En el presente trabajo, se analiza la hidrodinámica de un tanque de recirculación de agua empleado en acuacultura, aplicando simulación por computadora a través de técnicas CFD, demostrando la importancia de realizar simulaciones aplicando métodos numéricos, para la obtención de parámetros hidrodinámicos, principalmente, los campos de velocidad y turbulencia ante diversos escenarios de operación de un sedimentador tipo hidrociclón. Los resultados obtenidos demuestran que los principales factores que influyen en la hidrodinámica del tanque y del sedimentador son: la forma y distribución de rejillas del sedimentador, así como el diámetro del mismo. El efecto que producen dichas rejillas, son diversas variaciones en la distribución de velocidades del tanque y principalmente dentro del sedimentador, afectando las condiciones óptimas del flujo para la sedimentación de partículas y por ende la eficiencia en la remoción de sedimentos dentro del tanque. Con los resultados obtenidos mediante la aplicación de CFD fue posible relacionar la hidrodinámica del sedimentador con su diámetro y estructura de rejillas, logrando tener un flujo idóneo en el tanque para al sano desarrollo de los peces y un flujo con velocidad total máxima de 2 cm/s dentro del sedimentador, suficiente para lograr la sedimentación de partículas, y con ello generar un sistema con características de auto-limpieza.
9
Moghimi, Ardekani Mohammad. "Optical thermal and economic optimisation of a linear Fresnel collector". Thesis, University of Pretoria, 2017. http://hdl.handle.net/2263/61313.
Testo completoAbstract (sommario):
Solar energy is one of a very few low-carbon energy technologies with the enormous potential to grow to a large scale. Currently, solar power is generated via the photovoltaic (PV) and concentrating solar power (CSP) technologies. The ability of CSPs to scale up renewable energy at the utility level, as well as to store energy for electrical power generation even under circumstances when the sun is not available (after sunset or on a cloudy day), makes this technology an attractive option for sustainable clean energy. The levelised electricity cost (LEC) of CSP with thermal storage was about 0.16-0.196 Euro/kWh in 2013 (Kost et al., 2013). However, lowering LEC and harvesting more solar energy from CSPs in future motivate researchers to work harder towards the optimisation of such plants. The situation tempts people and governments to invest more in this ultimate clean source of energy while shifting the energy consumption statistics of their societies from fossil fuels to solar energy.
Usually, researchers just concentrate on the optimisation of technical aspects of CSP plants (thermal and/or optical optimisation). However, the technical optimisation of a plant while disregarding economic goals cannot produce a fruitful design and in some cases may lead to an increase in the expenses of the plant, which could result in an increase in the generated electrical power price.
The study focused on a comprehensive optimisation of one of the main CSP technology types, the linear Fresnel collector (LFC). In the study, the entire LFC solar domain was considered in an optimisation process to maximise the harvested solar heat flux throughout an imaginary summer day (optical goal), and to minimise cavity receiver heat losses (thermal goal) as well as minimising the manufacturing cost of the plant (economic goal). To illustrate the optimisation process, an LFC was considered with 12 design parameters influencing three objectives, and a unique combination of the parameters was found, which optimised the performance. In this regard, different engineering tools and approaches were introduced in the study, e.g., for the calculation of thermal goals, Computational Fluid Dynamics (CFD) and view area approaches were suggested, and for tackling optical goals, CFD and Monte-Carlo based ray-tracing approaches were introduced. The applicability of the introduced methods for the optimisation process was discussed through case study simulations. The study showed that for the intensive optimisation process of an LFC plant, using the Monte Carlo-based ray-tracing as high fidelity approach for the optical optimisation objective, and view area as a low fidelity approach for the thermal optimisation objective, made more sense due to the saving in computational cost without sacrificing accuracy, in comparison with other combinations of the suggested approaches.
The study approaches can be developed for the optimisation of other CSP technologies after some modification and manipulation. The techniques provide alternative options for future researchers to choose the best approach in tackling the optimisation of a CSP plant regarding the nature of optimisation, computational cost and accuracy of the process.Thesis (PhD)--University of Pretoria, 2017.
Mechanical and Aeronautical Engineering
PhD
Unrestricted
10
Gomes, Marc Faria. "Internal ballistics simulation of a solid propellant rocket motor". Master's thesis, Universidade da Beira Interior, 2013. http://hdl.handle.net/10400.6/1980.
Testo completoAbstract (sommario):
In the design and development of solid propellant rocket motors, the use of
numerical tools able to simulate, predict and reconstruct the behaviour of a given
motor in all its operative conditions is particularly important in order to decrease
all the planning and costs.
This study is devoted to present an approach to the numerical simulation of a
given SPRM internal ballistics, NAWC no. 13, during the quasi steady state by
means of a commercial numerical tool, ANSYS FLUENT.
The internal ballistics model constructed in this study is a 2-D axisymmetric
model, based on several assumptions. Among them is the assumption that there
is no contribution of the erosive burning and the dynamic burning in the burning
rate model.
The results of the internal ballistics simulation are compared with the results
found in the bibliographical research, thus validating the model that has been set
up. The validation of the results also allows us to conclude that the assumptions
made in the construction of the model are reasonable.
Suggestions and recommendations for further study are outlined.Na concepção e desenvolvimento de motores foguete sólidos, o uso de ferramentas numéricas capazes de simular, prever e reconstruir o comportamento de um dado do motor em todas as condições operativas ´e particularmente importante, a fim de diminuir todos os custos e planeamento. Este estudo ´e dedicado a apresentar uma abordagem para a simulação numérica de balística interna de um determinado motor foguete de propelente sólido, Naval Air Warfare Center no. 13, durante a fase quasi steady state por meio de uma ferramenta numérica comercial, ANSYS FLUENT. O modelo de balística interna construído neste estudo é um modelo axissimétrico 2-D. Tem por base vários pressupostos. Entre eles, está o pressuposto de que não há contribuição da queima erosiva e da queima dinâmica no modelo da taxa de queima. Os resultados da simulação balística interna são comparados com os resultados encontrados na pesquisa bibliográfica, validando assim, o modelo que foi construído. A validação dos resultados também nos permite concluir que os pressupostos assumidos na construção do modelo são razoáveis. Sugestões e recomendações para um estudo mais aprofundado são delineadas.
11
Haake, Eric. "Simulation and Analysis of Closed System Methane Combustion". Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1607530059350376.
Testo completo
12
Rogers, Charles. "Computational Fluid Dynamics Analysis of an Ideal Anguilliform Swimming Motion". ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1940.
Testo completoAbstract (sommario):
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.
13
Balobanov, Damir. "Vliv způsobu čerpání experimentální komory na průběh teploty plynu". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442558.
Testo completoAbstract (sommario):
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.
14
Drexler, Pavel. "CFD analýza proudění vzduchu pro různé typy průtokoměrů". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220888.
Testo completoAbstract (sommario):
There are some basic information about pressure sensors and flow in the first part of my diploma thesis. For example turbulent and laminar flow, construction of pressure sensors and basic information abaut Ansys and –Fluent. Main part of this thesis is focused on CFD simulation of pressure and velocity in the vicinity of pressure sensors. I confront this simulated values with measured values in final part of this thesis.
15
Mroue, Hassan. "Numerical and experimental investigation of a multi-pass heat-pipe-based heat exchanger". Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16131.
Testo completoAbstract (sommario):
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.
16
Kafeel, Khurram. "Modelling and simulation of two-phase closed thermosyphones using two-fluid method". Thesis, University of Manchester, 2014. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:239221.
Testo completoAbstract (sommario):
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.
17
Hinse, Mathieu. "Investigation of Transpiration Cooling Film Protection for Gas Turbine Engine Combustion Liner Application". Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42425.
Testo completoAbstract (sommario):
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.
18
Langer, Lukáš. "Modelování Lithium Iontových akumulátorů pomocí ECM". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-319565.
Testo completoAbstract (sommario):
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.
19
Kácal, Jan. "Optimalizace klapek pro letouny SKYLEADER". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319260.
Testo completoAbstract (sommario):
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.
20
Kapell, Jennie. "Analysis of the Inner Flow in the Wave Energy Converter WaveTube". Thesis, KTH, Tillämpad termodynamik och kylteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102293.
Testo completoAbstract (sommario):
Wave energy technology is currently growing and gaining popularity. With around 100 separate technologies researched globally in over 25 countries wave energy are believed to soon be able to compete with other renewable sources such as wind energy. One of the new technologies is WaveTube; a wave energy converter currently under development and in need of technical verification. The basic idea of WaveTube is a partially submerged container with an enclosed fresh water volume. The kinetic energy of the ocean waves are transferred onto the floating container, creating an inner flow in the structure and electricity is generated as the fresh water flows through turbines. Previous small-scale model tests have confirmed the basic idea of WaveTube and an inherent continuation is visualizing and evaluating the inner flow using Computational Fluid Dynamics. A simplified 2D simulation where the WaveTube structure is subject to a pure sinusoidal, rotational motion was believed to be able to give useful information about the inner flow field. However, this Master Thesis project shows that a simulation using ANSYS Fluent of this case is not a successful approach. With inner moving parts a so called dynamic mesh was required, which updates the mesh as the boundaries move. In order for this method to be successful the mesh needs to be of high quality. However, for the complex geometry that WaveTube is no mesh was found to meet the requirements and the calculations using the Volume of Fluid method were not able to proceed.
21
Koren, Dejan. "Computational Fluid Dynamics Unstructured Mesh Optimization for the Siemens 4th Generation DLE Burner". Thesis, KTH, Mekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-178034.
Testo completoAbstract (sommario):
Every computational fluid dynamics engineer deals with a never ending story – limitedcomputer resources. In computational fluid dynamics there is practically never enoughcomputer power. Limited computer resources lead to long calculation times which result inhigh costs and one of the main reasons is that large quantity of elements are needed in acomputational mesh in order to obtain accurate and reliable results.Although there exist established meshing approaches for the Siemens 4th generation DLEburner, mesh dependency has not been fully evaluated yet. The main goal of this work istherefore to better optimize accuracy versus cell count for this particular burner intended forsimulation of air/gas mixing where eddy-viscosity based turbulence models are employed.Ansys Fluent solver was used for all simulations in this work. For time effectivisationpurposes a 30° sector model of the burner was created and validated for the meshconvergence study. No steady state solutions were found for this case therefore timedependent simulations with time statistics sampling were employed. The mesh convergencestudy has shown that a coarse computational mesh in air casing of the burner does not affectflow conditions downstream where air/gas mixing process is taking place and that a majorpart of the combustion chamber is highly mesh independent. A large reduction of cell count inthose two parts is therefore allowed. On the other hand the RPL (Rich Pilot Lean) and thepilot burner turned out to be highly mesh density dependent. The RPL and the Pilot burnerneed to have significantly more refined mesh as it has been used so far with the establishedmeshing approaches. The mesh optimization has finally shown that at least as accurate resultsof air/gas mixing results may be obtained with 3x smaller cell count. Furthermore it has beenshown that significantly more accurate results may be obtained with 60% smaller cell count aswith the established meshing approaches.A short mesh study of the Siemens 3rd generation DLE burner in ignition stage of operationwas also performed in this work. This brief study has shown that the established meshingapproach for air/gas mixing purposes is sufficient for use with Ansys Fluent solver whilecertain differences were discovered when comparing the results obtained with Ansys Fluentagainst those obtained with Ansys CFX solver. Differences between Fluent and CFX solverwere briefly discussed in this work as identical simulation set up in both solvers producedslightly different results. Furthermore the obtained results suggest that Fluent solver is lessmesh dependent as CFX solver for this particular case.
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Mane, Prashant V. "Computational Study of Poppet Valves on Flow Fields". Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1391608907.
Testo completo
23
Ekman, Petter. "A Sensitivity Study of Some Numerical and Geometrical Parameters Affecting Lift". Thesis, Linköpings universitet, Mekanisk värmeteori och strömningslära, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-124197.
Testo completoAbstract (sommario):
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.
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Jahan, Georgina. "Modeling of Heat Transfer in LDConverter (BOF) Lining". Thesis, KTH, Tillämpad processmetallurgi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93768.
Testo completoAbstract (sommario):
During the production of steel in the LD converter the refractory lining is exposed to high temperature emulsion of steel, slag and gas. It protects the steel body of the vessel to come in contact with the molten steel.The main purpose of this work was to observe the temperature distribution profile in converter refractory lining which is very important to understand the life of the refractory lining of the LD converter.In this study, a three dimensional (3D) heat transfer model for the refractory lining of converter was developed. The lining of the refractory material was considered as magnesite brick for inner lining, dolomite for intermediate lining and steel shell as outer part. In order to do the numerical modeling, the CFD software Ansys Fluent 13.0 was used. After considering the proper dimensions, meshing, properties of the lining material and boundary conditions, the modeling in Ansys was performed in two stages. In the first stage, the modeling was performed by assuming that the converter is already heated and the inside temperature of the furnace is 1923K and the outside temperature of the steel body is 300K. In the second stage, the temperature change of the molten steel, slag and the gas was considered as function of blowing time and slag height based on theories from different references. Firstly, the three dimensional (3D) heat transfer model was used for the refractory lining of the converter to show transient heat flow through the lining at different times. Secondly, 3D modeling results from fluent 13.0 was used to develop temperature distribution profile through the lining at different height for different time steps and at different positions with time and also along the converter height from the bottom to top. It has been noticed that refractories in the lining in contact with steel and slag must be of good quality for the reduction of wear cost and downtime and therefore the reduction of refractory cost per ton of steel production.
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Jybrink, Anton. "Dynamic CFD Modelling of Deploying Fins During Transitional Ballistic". Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70758.
Testo completoAbstract (sommario):
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.
26
Mačák, Martin. "Modelování magnetohydrodynamických jevů". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377336.
Testo completoAbstract (sommario):
Theoretical part of this thesis is dedicated to the theoretical basis of electric conduction phenomena in fluids and method of calculation of magnetohydrodynamic phenomena. In the experimental part, computational modules have been developed to complement and augment the use of commercial simulation programs for simulation in the field of magnetohydrodynamics. On practical examples of mass spectrometer simulation, Einzel lens, electron movement and electric circuit breaker, the functionality of the computational models and the correctness of the obtained results were documented. Created computational modules can be used to design and optimize products using magnetohydrodynamic phenomena.
27
Matteucci, Simona. "Numerical Modelling of a Flameless Combustor". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Cerca il testo completoAbstract (sommario):
Flameless combustion can be adopted as a low-emission combustion regime in the aviation sector, which is one of the biggest contributors to NOx emissions and is expected to grow in the near future. Nevertheless, several issues must be solved before any practical applications. Effective design procedure must deal with either combustion or heat transfer phenomena occurring at extremely low—temperature conditions. To this aim, experimental and numerical analyses focused on the characterization of fuel/oxidant behaviour are strongly needed and represent an essential step for further development.
Besides, the complexity of the analysed technological system requires advanced tools for the definition of the chemical kinetics, for the burner designs and more in general for the definition of aviation equipment design. In this light, the thesis has been addressed to the study of flameless combustion mechanisms within a combustion chamber prototype developed in the Faculty of Aerospace Engineering at TU Delft. In particular, the temperature and species concentration fields have been analysed. The CFD tool which will be used is Ansys Fluent together with two detailed reaction mechanisms (KIBO and RDM19).
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Kent, Jason A. "Numerical and Experimental Analysis of a TurboPiston Pump". ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1189.
Testo completoAbstract (sommario):
The TurboPiston Pump was invented to make use of merits such as, high flow rates often seen in centrifugal pumps and high pressures associated with positive displacement pumps. The objective of this study is to manufacture a plastic model 12†TurboPiston Pump to demonstrate the working principle and a metal prototype for performance testing. In addition, this research includes the study of the discharge valve to estimate the valve closing time and fluid mass being recycled back into the cylinder through hand calculations. Furthermore, a transient simulation was performed in CFD using Fluent to provide a better estimate of what will happen in the actual pump while running. Additionally, an experimental rig was designed to investigate the performance of the first generation valve on the TurboPiston Pump known as the flapper valve. Means to improve the hydrodynamic performance of both valves have been identified for future study.
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Lindstens, Robin. "Computational fluid dynamics calculations of a spillway’s energy dissipation". Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-417950.
Testo completoAbstract (sommario):
To make sure that a dam is safe it is important to have good knowledge about the energy dissipation in the spillway. Physical hydraulic model tests are reliable when investigating how the water flow behaves on its way through the spillway. The problem with physical model testing is that it is both expensive and time consuming, therefore computational fluid dynamics, CFD, is a more feasible option. This projects focuses on a spillway located in Sweden that Vattenfall R&D built a physical model of to simulate the water discharge and evaluate the energy dissipation in order to rebuild the actual spillway. The main purpose of this project is to evaluate if the physical hydraulic test results can be reproduced by using CFD, and obtain detailed results about the flow that could not be obtained by physical testing. There are several steps that need to be completed to create a CFD-model. The first step is to create a geometry, then the geometry needs to be meshed. After the meshing the boundary conditions need to be set and the different models, multiphase model and the viscous model, need to be defined. Next step is to set the operating conditions and decide which solution method that will be used. Then the simulation can be run and the results can get extracted. In this project two CFD simulations were performed. The first simulation was to be compared with the physical hydraulic model test results and the second CFD simulation was of the rebuilt spillway. The results proved that the physical model test results could be recreated by using CFD. It also gave a better understanding of how the energy dissipation was in the spillway and indicates that the reconstruction of the actual spillway was successful since the new spillway both had a higher water discharge capacity and better energy dissipation.
30
Flídr, Karel. "Vliv tvaru sacích kanálů na čerpání u scintilačního detektoru". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221082.
Testo completoAbstract (sommario):
The thesis is concerned with the design of the shape of suction canals used for pumping in the scintillation detector. The goal is to perform analysis of the model of the detector according to the current conception and then perform an optimalisation of the suction canals as per demands to their function. In the beginning of the thesis the history of the microscope and electron microscopy is described. The next chapter is focused on a more detailed description of ESEM. The following charter is dedicated to describing the scintillation detector.The thesis recounts the kinds of liquid flow. In conclusion the programs SolidWorks and Ansys Fleunt are described. Next part of this thesis describes in detail parameters‘ settings of simulation calculation. Following chapter introduces designed changes of suction channels shape and its results are shown and described.
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Repko, Ilia. "Matematicko-fyzikální analýza klimatické komory". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-377102.
Testo completoAbstract (sommario):
This work deals with the mathematical and physical analysis of the climatic chambers. The theoretical part describes the issue of climatic chambers, software SolidWorks and ANSYS Fluent, basic equations describing fluid status and fluid turbulence. The practical part of the thesis is to create the model of climatic chamber in CAD system SolidWorks and simulation of flow and and temperature distribution by ANSYS Fluent. At the end of the work the results are analyzed and evaluated.
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Yang, Ming. "Numerical Modeling of Aluminum Sampling Process". Thesis, KTH, Materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-241102.
Testo completoAbstract (sommario):
Castings of aluminum alloys are widely used in the automotive and aerospace industries since they play a significant role in improving the performance and fuel efficiency. In aluminum industries, sampling is the most common method to evaluate the inclusion levels which is a key indicator for the quality of the aluminum alloys. Since how the filling process and solidification process will influence the inclusion characteristics during the sampling procedure is of great importance, the objectives of this work is to create a the two-phase flow model to simulate the filling process and solidification process, as well as calculate the particles movement in the whole sampling procedure. Computational Fluid Dynamics (CFD) modeling was used and this work was performed in the software ANSYS FLUENT. A numerical two dimensional (2D) axisymmetric model was built to simulate the sampling procedure with the assumption that the filling could be done along the main axis automatically. First, the initial solidification during the filling was taken into account without particle injection. The realizable k − ε turbulence model was used to model the effects of the turbulence. Several simulations with different inlet filling rate, different initial filling temperature and different inlet diameter was calculated to see the influence on the solidification behavior. Then, the whole sampling system was modeled with particle injection. The Discrete Phase Model (DPM) was used to simulate the particle motion in the melt and the focus was on the influence of the initial solidification on the inclusion distributions. Finally, the optimal sampling position inside the aluminum sampler mold was calculated.Gjutningar av aluminiumlegeringar används ofta inom bil-, och flygindustrin eftersom de spelar en viktig roll för att förbättra prestanda och bränsleeffektivitet. Inom aluminiumindustrin är provtagning den vanligaste metoden att utvärdera mängden inneslutningar i smältan, vilket är en nyckelindikator för kvaliteten på aluminiumlegeringarna. Eftersom både fyllnads- och stelningsprocessen kommer att påverka inneslutningskarakteristiken är provtagningsproceduren av stor betydelse. Syftet med detta arbete är att skapa en två-fasflödesmodell för att simulera fyllnings-, och stelningsprocessen, samt att beräkna partikelrörelserna under provtagningsförfarandet. Computational Fluid Dynamics (CFD) modellering användes och arbetet har utfördes med mjukvaran ANSYS FLUENT. En numerisk tvådimensionell (2D) axisymmetrisk modell byggdes för att simulera provtagningsproceduren med antagandet att påfyllningen kan göras automatiskt längs huvudaxeln. Till att börja med betraktades det första stelnandet under fyllningen utan partikelinjektion. En antagen k - ε turbulensmodell användes för att modellera effekten av turbulens. Flera simuleringar med olika inloppshastighet, påfyllningstemperatur och inloppsdiametrar beräknades för att se påverkan på stelningsbeteendet. Därefter modellerades hela provtagningsmodellen med partikelinjektion. En Diskret Fasmodell (DPM) användes för att simulera partikelrörelsen i smältan och fokus var inverkan av det initiala stelnandet på inneslutningsfördelningen. Slutligen beräknades den optimala provtagningspositionen inuti aluminiumprovformen.
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Kohont, Alexander, e Roger Can Isik. "TERMISKT SMARTA HANTERINGSSYSTEM FÖR LITIUMJONBATTERIER : Analys av litium-jonbatteriets termiska beteende". Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-55065.
Testo completoAbstract (sommario):
Batteries play an important role in a sustainable future. As the development for better andsmarter batteries continues, new areas of use emerge boosting its demand. Controlling thetemperature of a battery cell is a vital objective to ensure its longevity and performance. Bothcooling and heating methods can be applied to keep the temperature within a certain rangedepending on its need. This study will review the technical aspects of lithium-ion batteries,observe the different thermal management systems and cooling methods, and lastly examinethe required cooling flow needed for a battery cell to prevent its temperature from rising tocritical levels during its discharge. Using CFD ANSYS Fluent as a simulation tool, the resultsshow that different charging rates, in terms of C-rate, require different rates of mass flow tocontrol the temperature. Simulating the cell with natural convection, the cell peaks at hightemperatures even at lower C-rates, reaching up to 36,4°C and 48,8°C for 1C and 2C,respectively. Applying the cooling method with a flow rate of 0,0077kg/s reduces thetemperature significantly, resulting in temperatures of 26,95°C and 31,27°C for 1C and 2C,respectively.
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Barassa, Jonathan, e Rickard Nordlöf. "Numerical Study on Air Demand of Free Surface Flows in a Discharge Tunnel". Thesis, Uppsala universitet, Institutionen för fysik och astronomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-414989.
Testo completoAbstract (sommario):
Aeration issued through a ventilation shaft is an important measure to prevent cavitation and large gauge pressure in flood discharge tunnels. In order to dimension the ventilation shaft appropriately, itis necessary to have a good understanding of the air-water flow in the tunnel. In this study, the multiphase flow through a discharge tunnel was simulated in the computational fluid dynamics (CFD) software ANSYS Fluent. Since the flow was separated, the simulation setup used the volume of fluid (VOF) multiphase model, that could track the water surface. Furthermore, the so called RNG k-epsilon turbulence model was used. The CFD model was validated with measured data provided from two open channel experiments carried out on a scaled model at Sichuan University. To ensure mesh independence, grid convergence index (GCI)studies were performed for the two validating cases. After the validation, a top wall and a ventilation shaft was added to the CFD model. The flow was then simulated for four different shaft designs and four different water inlet velocities. The air demand and air supply for the various scenarios could thereby be calculated. The results of this study were also compared with previous research on multiphase flow through tunnels with similar design. It was concluded that the air flow downstream in the tunnel converged for the two larger designs. It was also concluded that the air demand in the tunnel was satisfied for the larger ventilation shafts. A smaller study on cavitation was made and the risk was considered non-existent for all the simulated cases.
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Novotný, Jakub. "Numerický model teplotního pole Li-Ion akumulátoru při vybíjení". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-319562.
Testo completoAbstract (sommario):
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.
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Olsson, Patrik. "Martian Caves as Special Region Candidates : A simulation in ANSYS Fluent on how caves on Mars are, and what their conditions would be for being considered as special regions". Thesis, Luleå tekniska universitet, Rymdteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70957.
Testo completoAbstract (sommario):
One of the most interesting questions about Mars is if life ever existed on it. One of the main requirements for life to exist as we know it is the presence of liquid water. It has been suggested by Martín-Torres et al. (2015a) that a daily-transient liquid water cycle takes place on the surface of Mars through deliquescence and efforescence (binding and releasing of water vapour) of perchloratic salts in the Martian soil. Given the right conditions regarding water activity and temperature, certain planetary areas have been defined as Special Regions where there is a chance of life-form reproduction to occur (Kminek et al. 2017). Sub-surface cavities and caves are defined as such and are still a relatively unexplored and not yet studied feature of the Martian surface. This report is an assessment of the environmental conditions in Martian subsurface cavities such as caves and how it can be considered as a Special Region. Based on observations of lava tubes made by Cushing and Titus (2010) with atmospheric and thermal data from REMS on board the Curiosity rover by Martín-Torres et al. (2015b), simulation models were set up in ANSYS Fluent to examine the behaviour of the temperature and relative humidity within these caves. Different properties of the studied models included size, shape, inclination, materials of the ground composition and air flow behaviour. The results showed that a cave roof with a thickness greater than 1-2 m prevents the ground temperature variation during the day to have any considerable impact on the air temperature in the cave which implies that the thermal waves are the main driving factor of the thermal environment in larger models. The average temperature and relative humidities throughout the entire models resulted in unfavourable conditions (relative humidity under 20% RH) to allow for any perchloratic salts to hydrate or form brines. The most interesting results were found in smaller models where different phenomena with higher relative humidity near the floor and in corners occurred for several hours during the same day. This happened at certain times during the day (LMST 7 and 17) when the inlet temperature surpassed the average temperature in the cave and resulted in relative humidities of up to 90% RH which potentially could allow perchloratic salts to stay in brine form, or at least in a hydrated state throughout the day. While the low temperatures in today's Martian caves may be too harsh for life forms to exist, a previous warmer climate might have allowed for extremophiles to thrive in highly saline solutions. This could be an implication that Martian caves should be defined as Special Regions and that further studies should be done on the subject.
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Zetterström, Sebastian. "Evaluation of a suction pyrometer : By heat and mass transfer methods". Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36450.
Testo completoAbstract (sommario):
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
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Succi, Martino. "Analysis of the efficiency of air and steam-assisted flares on offshore platform". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Cerca il testo completoAbstract (sommario):
Gas Flaring is nowadays uniquely recognized as a major environmental threat. In addition to that, it has been estimated that flaring operations are one potential under-reported or non-reported pollutants source.
Studying a flaring process, characterizing its emissions, and evaluating key indicators, such as the destruction & removal efficiency (DRE) and/or the combustion efficiency (CE), may be extremely difficult primarily due to (1) Type of Industrial Plant & Composition of the Stream to be flared, (2) Operation Mode, (3) Flare Design, (4) Meteorological Conditions, and (5) Possible Flare Malfunctioning.
As a consequence of that, being able to correctly model a flaring process with the help of Computational Fluid Dynamics (CFD) could represent a valid alternative to expensive flare tests, since grab samplings or remote sensing are costly operations. Moreover, it is impossible to test during startup, shutdown, and maintenance periods.
This study makes use of one of the most popular CDF software in order to investigate the interaction between crosswind and fuel jet velocity and to determine the optimal amount of assist air/steam to be provided to maximize the combustion efficiency for a given flaring apparatus.
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Shindle, Bradley W. "Computational Investigations of Polymer Sheet Breakup for Optimization of Devolatilization Processes in Steam Contactors". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1509379799347531.
Testo completo
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Vince, Tomáš. "CFD analýza tepelného zatížení trubkovnice". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443458.
Testo completoAbstract (sommario):
This diploma thesis focuses on the phenomena of multiphase flow in a steam generator as a one of probable causes of tubes and tubesheet weld cracking. In the first part of the work, a research was carried out focusing on the boiling and the phenomenon of two-phase flow in technical applications, its characteristics and properties. The thesis continuous with an overview of available numerical multiphase models in the ANSYS Fluent 2021 R1 and a research of previously published works focused on two-phase flow with the presence of boiling. The research is followed by a description of the particular boiler, which is part of the nitric acid production plant in the chemical company DUSLO, a.s., its operating conditions and a more detailed description of the issue that is being addressed in this thesis. The second part of the work continuous with a description of the computational model, including a description of the geometry of the model and used simplifications, the computational mesh and the description of boundary conditions. Important part is the description of calculation setting of steady-state and transient CFD simulations in ANSYS Fluent. Finally, the results of the two-phase flow calculation are presented and then discussed in the conclusions.
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Hřešil, Tomáš. "Analýza chlazení koncentrátorového fotovoltaického článku". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220330.
Testo completoAbstract (sommario):
This project solves the problem of cooling the photovoltaic cell. Solar cell was modeled according to a real model in SolidWorks, and subsequently created the model was simulated in SolidWorks Flow Simulation and Ansys Fluent. The use of both systems allow a comparison of their possibilities in the field of heat transfer and their suitability for the case. The conclusion summarizes the first results and outline further developments cooling design to optimize the performance of the solar cell.
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Mackovík, Matěj. "Optimalizace chlazení oleje letounu VUT 100". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229449.
Testo completoAbstract (sommario):
The mein objective of this diploma thesis is to optimize the oil cooler of the VUT 100 aircraft, so that it complies with the CS-23 regulation and requirements of the engine producer. This is fulfilled by using of suitable oil cooler and by optimization of the air duct. Computational Fluid Dynamics approach – namely Ansys Fluent software package is used for it.
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Allen, Jeremy L. "The Effect of Baffle Arrangements on Flow Uniformity in a Manifold for a Unique Solid Oxide Fuel Cell Stack Design". Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1320851931.
Testo completo
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Vobejda, Radek. "Výpočtové modelování aerodynamického hluku způsobeného bočním zrcátkem automobilu". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401556.
Testo completoAbstract (sommario):
The master’sthesis deals with numerical modelling of aerodynamic noisewhich arisesinside of the carcabin. In the first part ofthe thesis simplified model of geometry of the car and of the inside acoustic pressure arecreated. After that numerical analysis of created models of geometry are doneandvarious models of turbulenceare discussed. The results of these CFD simulationswhere then used for changing the model of geometry of the wing mirror. Outputs of these simulations were used for solving the numerical analysis of noise in the car cabin.
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Jurka, Jiří. "Posuzování provětrávaných podlahových konstrukcí". Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-234549.
Testo completoAbstract (sommario):
Air insulation, especially its efficiency, is often underestimated and most often it is recommended as combination of several methods by our experts. It is known that flowing air used to eliminate excessive humidity in lower construction is insignificantly promoted. Already our ancestors in ancient Rome had experience with implementation of air insulations. However, nowadays such design is connected with many doubts and it forces us to use sense, especially knowledge of construction physics. So it urges higher technical precision when designing functional ventilation system. Each building is actually a unique object, with regard to its position and used properties, that is why certain natural conditions must be accepted when designing. It is more complicated and figuratively speaking it can be written in c. 20 equations of twenty unknowns. Other problems arise in unknown coefficients to individual parameters and their effects. From another point of view it is the issue of changing air during the day, passing fronts, annual cycles and all of these in relation to internal environment of the building, materials used in the construction, land properties of rocks, and last but not least, relation to the terrain around the building. Then there are the effects of the building's altitudes etc. In total they are cycles with sine character of dampening and drying. The thesis discusses how to test the functionality of AIR insulations designed for the floor ventilation in historic buildings and follows on from the previously published articles. A flow analysis is being performed on an object of the city of Žirovnice which has been registered in the list of cultural monuments and was built as a brewery in the years 1589-1592 on the site of an older medieval building. This article brings new air-flow element. The aim of the article is to analyse in detail the air flow in a specific floor void with the aid of modern CFD programs and experimental measurements using the ALMEMO
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Boga, Gabriele. "Analisi aerodinamica preliminare di un veicolo alimentato ad energia solare". Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/14285/.
Testo completoAbstract (sommario):
L’obiettivo di questo lavoro è lo studio della variazione dei carichi aerodinamici per piccole variazioni della geometria su un veicolo da competizione ad energia solare. Questa analisi si inserisce nell’ottimizzazione aerodinamica di dettaglio. Il veicolo oggetto di studio è Emilia IV, auto sviluppata dal team Unibo Onda Solare. L’attività si è svolta tramite lo studio di tre configurazioni ottenute inclinando la parte superiore del veicolo originale di +2° e di -2°. Per le simulazioni fluidodinamiche è stato utilizzato il codice di calcolo commerciale Ansys Fluent. Le simulazioni sono state condotte con una velocità del flusso indisturbato di 20 m/s e con un numero di Reynolds calcolato sulla lunghezza della vettura di 6 milioni. Per la modellazione della turbolenza è stato utilizzato il modello k-epsilon realizable. È stato considerato uno strato limite turbolento per tutta la lunghezza del veicolo. La validazione del modello utilizzato è stata effettuata sulla geometria originale di Emilia IV tramite dati ottenuti precedentemente da simulazioni condotte con codici di calcolo Open Source (Open Foam) da ricercatori della Facoltà di Ingegneria di Forlì. La validazione della mesh è stata effettuata tramite simulazioni con quattro griglie di calcolo con numero di elementi crescente per verificarne la convergenza. Il numero di elementi della mesh definitiva è di 8 milioni composta da celle tetraedriche e da celle prismatiche. Si è data particolare rilevanza al coefficiente di resistenza delle tre vetture. Il modello utilizzato ha fornito risultatati sufficientemente accurati al fine di questo lavoro. La geometria originale si è dimostrata essere la più efficiente in termini di resistenza aerodinamica.
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Ringe, Shivansh. "Designing of One Directional Wave Tank". Thesis, Uppsala universitet, Institutionen för elektroteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-423335.
Testo completoAbstract (sommario):
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.
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Kerestes, Jared N. "Numerical Investigation of Flow Around a Deformed Vacuum Lighter-Than-Air Vehicle". Wright State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=wright1622235951947085.
Testo completo
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Hamberg, Micaela, e Signe Dahlin. "Numerical Study on Hydrodynamic Characteristics of Flood Discharge Tunnel in Zipingpu Water Conservancy Project : Using RANS equations and the VOF model". Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-387206.
Testo completoAbstract (sommario):
To avoid the large amount of damage that floods can cause, spillway tunnels are used to control water levels. To ensure the safety of water transportation through spillway tunnels, the behaviour of the water throughout the tunnel is important to know. Physical experiments are time consuming and expensive, hence CFD simulations are a profitable option for investigating the performance of the spillway tunnel. In this project, simulations of water flow in a spillway tunnel were executed. A three dimensional model of the spillway tunnel in Zipingpu Water Conservancy Project was created in the software ANSYS Gambit. A coarse, middle and fine mesh with both hexahedral- and tetrahedral elements were also created for the model in ANSYS Gambit. The meshes were imported to ANSYS Fluent where the simulations, and a convergence analysis were made. The water flow was set to be described by the Reynolds-Averaged Navier-Stokes model, using the pressure solver, k-epsilon model and the VOF model. Physical experiments had previously been performed, and the simulated results were compared to these, in an attempt to find the parameters to replicate the experimental results to the greatest extent possible. The inlet velocity of the tunnel was known and the inlet boundary was set as a velocity inlet. The ceiling of the tunnel was set as a pressure inlet, the floor and walls were set as wall, and the outlet was set as pressure outlet. The simulated results showed similar behavior as the experimental results, but all differed from the experimental results. The grid convergence index, estimating the results' dependency on the mesh was 6.044 %. The flow was analyzed, and where the flow had unfavorable characteristics, such as a high cavitation number, the geometry of the spillway was altered in ANSYS Gambit to investigate if an improved geometry for the spillway tunnel could be found. The water flow in the revised geometry was simulated in ANSYS Fluent, and results showing flow with lower cavitation numbers was found.
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Lepltová, Kristýna. "Matematicko - fyzikální analýza dynamického tlaku pro experimentální diferenciální komoru". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-376980.
Testo completoAbstract (sommario):
This thesis is based on the series of scholarly article dedicated to the issue of pumping in the differential scanning chamber of an environmental scanning microscope. The thesis is based on Danilatos’s study where the pumping of the differential pumped chamber is solved by means of the Monte Carlo statistical method. The thesis analyzes gas flow in the experimental chamber using the Pipot tube. The analyses will be used for the design of the experimental chamber which will serve for the experimental evaluation of the flow results in the chamber using the continuum mechanics.