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Analysis of ventilation effect of radial channels in the rotor of electrical machines
Kratochvílová, Hana ; Marcián, Petr (referee) ; Vlach, Radek (advisor)
This thesis deals with the determination of a ventilation effect of the radial channel, that is used in a rotor of an electrical motor. CFD simulations of the channel are done in Ansys CFX software. The first chapter explains the basic theory of fans, flow, thermomechanics, CFD and structural effects of rotation on the channel. The second chapter focuses on the determination of the fan curve, the power curve, and the efficiency curve. Different types of turbulence and fluid compressibility models are used for simulations and their influence on the result is evaluated. The third part evaluates the design of the radial channel from a structural point of view.
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Inlet recirculation of centrifugal pump
Heinz, Pavel ; Štefan, David (referee) ; Rudolf, Pavel (advisor)
This diploma thesis deals with the phenomenon appearing in hydrodynamic pumps at the sub-optimal flow rate. This phenomenon is inlet recirculation, which is an undesirable phenomenon in the suction of the pump. This recirculation causes cavitation, pressure pulsations and may cause clogging of the suction line. The main goal of the diploma thesis is CFD simulation for the recirculation mode, identification of the flow phenomena, and designs of possible measures to suppress inlet recirculation.
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CFD simulation flow of steam in the unregulated extraction of steam turbine
Filip, Patrik ; Pospíšil, Jiří (referee) ; Fiedler, Jan (advisor)
Diploma thesis named CFD simulation of the steam flow in the unregulated extraction of the steam turbine is about an analysis of the balance piston impact on the area of the steam turbine, where the extraction is located. First part describes basic knowledge of the steam turbine in general. At the end of this chapter, there is a description of the solved steam turbine. Next chapter is about introduction to the CFD. Practical part deals with a construction of 3D models, meshing and setting of the boundary conditions in the program ANSYS CFX. The main part of this thesis summarizes the results of the CFD simulation and stipulates the temperature range on the extraction pipe. In conclusion, there is a recommendation how to determine design temperature of the extraction pipe influenced by the balance piston.
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Optimization of Cooling Synchronous Machine
Makki, Zbyněk ; Rafajdus,, Pavol (referee) ; Kačor,, Pavol (referee) ; Janda, Marcel (advisor)
The main goal of doctoral thesis is optimization cooling of the synchronous machine. Problem is solved based on the finite element method with use of ANSYS software. Work is built up from theoretical part where is comparison of base equations for heat transfer and simulations for several models. Next part shows us two methods how simulate free and force convection. Depends on the better method from the previous two methods is used for next calculations with several algorithm which are used for find of best parameters for synchronous machine. Our control parameter is mass flow rate.
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Air flow load on a roof structure induced by a helicopter during erection works
Fidler, Tomáš ; Križan, Jiří (referee) ; Nevařil, Aleš (advisor)
Diploma thesis is focused on modeling rotor downwash generated by the main rotor of helicopter and analyzing its effects on the roof structure. Theoretical definition of rotor downwash flow is described in the first part of the text. Governing equations of computational fluid dynamics are briefly explained as well as boundary layer and finite volume method. Next part inquires into numerical simulation of rotor downwash based on height of rotor above the roof, shape of roof plane and climatic conditions. Results are compared with climatic load values provided by actual Czech construction standard in the end of the text.
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Wind loading of lightweight bridge-like structure
Hrubý, Pavel ; Kala, Jiří (referee) ; Nevařil, Aleš (advisor)
The present thesis is concerned with air flow over lightweight footbridge. Special attention is paid to flow-induced instabilities. The thesis opens with a theoretical elaboration on the phenomena related to the research matter. The next part investigates air flow over footbridge in a specific situation using numerical simulation in the Ansys CFX software. Finally, results are discussed in the light of chosen theoretical framework and relevant conclusions are presented.
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Model the flow of coolant in electrical machine
Potyš, Jiří ; Hájek, Vítězslav (referee) ; Janda, Marcel (advisor)
The thesis is focused on possibilities of asynchronous motors cooling with use of simulation at ANSYS Workbench program. It is divided into two parts. The first part deals with analyses of cooling medium circulation through ventilator and cooling medium circulation on the motor surface. As a result of the analyses is air speed distribution and air pressure representation. The second part of the thesis includes simulation of motor temperature rise both with cooling and without cooling at Ansys Workbench application together with temperature measurement of real asynchronous motor in the laboratory. For cooling purposes air circulation was used. The goal of my research is comparison of the computing results with the measured results.
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Ventilation calculations in synchronous machine
Judas, Jan ; Deeb, Ramia (referee) ; Janda, Marcel (advisor)
The aim of the project was to get familiar with the environment of ANSYS CFX, create several models of fans and synchronous machine model in Autodesk inventor, create model of cooling medium flow through the machine with these fans and evaluation of results. Firstly the thesis describes the synchronous machine itself, losses of the machine, the flow of power of synchronous machine and methods of its cooling. Next the thesis describes each kind of heat transfer, laminar and turbulent flow. The thesis also refers of kind of the fans and the program used to calculate the flow Ansys CFX, including the method that Ansys used to calculate. The work describes the individual modification of fans and setting of calculation in ANSYS. Then displays the results of the analysis these fans for different numbers of fan blades and for modification of the fan. Then the thesis analyzes selected modifications due to changing speed. In the last chapter shows the analysis of flow in the machine with three different fans. In particular, there is shown the mass flow rate, pressure and its distribution on areas for evaluation.
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Calculation of the cooling medium in the asynchronous
Trnka, Zbyněk ; Skalka, Miroslav (referee) ; Janda, Marcel (advisor)
The aim of this master´s thesis was to model the fan for the induction motor, and then to solve this model using Ansys CFX in the terms of flow, when considering the different speeds of rotation of the rotor. The introduction of this work is dedicated to basic terms and definitions from spheres of fluid flow, cooling of the electrical machines, especially to the cooling of the asynchronous machine. There is also attention paid to losses in this machine. Finally, there is modeled radial fan and an air gap of specified induction machine. By using Ansys CFX the flow, which passes from the fan into the air gap, is analyzed.
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Wind loads of building structures
Štěrba, Martin ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
The bachelor thesis deals with the analysis of the effects of wind load on building structures. In the context of the work is solved the numerical modeling of flow around the solid cylindrical bodies at high Reynolds numbers. To the simulations has been used computational software ANSYS CFX. The outputs of the work are the values of Strouhal numbers and the values of drag and lift coefficient depending on the Reynolds number.
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