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Design of a closed cooling circuit
Novotný, Tomáš ; Milčák, Pavel (referee) ; Kracík, Petr (advisor)
The aim of this bachelor thesis is to design a closed cooling circuit for specific technologies of the power plant machinery room, namely lubricating oil system, power generator and high pressure hydraulic system. The main task is to provide heat dissipation from each system to a central heat exchanger, which is one of the objectives of the thesis design. The work is divided into three parts. The first part deals with the basic description of the cooling circuits and their division. In the second part, the basic components of the cooling circuit and their functions are presented. The principle of heat sharing is also presented. In the third part of the paper, the actual design of the closed cooling circuit is presented, which includes the design of the central heat exchanger. The work includes a model of the piping, which is based on a basic heat balance and P&ID diagram. AVEVA E3D software was used for its creation. Based on the piping isometry and pressure losses in the individual devices, the pressure loss of the circuit is determined. Another objective of the work is the design of the expansion vessel. The problem is solved by using software suitable for solving each part of the design. The output of the work is a refrigeration circuit meeting the requirements for the specified conditions.
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Strength Analysis of Turbocharger Rotor of Stationary Internal Combustion Engine
Kejval, Dan ; Kudláček, Petr (referee) ; Novotný, Pavel (advisor)
Turbocharger rotors are highly stressed components exposed to significant thermo-mechanical loads. This thesis provides a literature review of this issue concerning turbocharger rotors and focuses on the thermal field analysis and structural analysis of the turbocharger rotor of a stationary internal combustion engine under different steady-state operating conditions, especially under maximum thermo-mechanical load. The analysis was conducted using Ansys Mechanical software, which allows for the calculation of the thermal field as well as the identification and evaluation of critical areas of the rotor using the finite element method. The result of the thesis is an assessment of the rotor's safety, including the risk of loosening the rings preloaded on the rotor shaft.
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Simplified design of heat exchangers using MS Excel
Konečný, Ondřej ; Jegla, Zdeněk (referee) ; Kilkovský, Bohuslav (advisor)
This bachelor thesis deals in the first part with the research, where the types of heat exchangers are briefly described. The next part contains the basic equations for the calculation of heat exchangers as well as different approaches to the calculation of these devices. The practical part of this thesis focused on the development of the calculation tool, the corresponding manual and the functionality checking with examples.
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Optimization of the cockpit ventilation system of a small transport aircraft
Vícena, Ondřej ; Charvát, Pavel (referee) ; Fišer, Jan (advisor)
This thesis deals with the optimization of the cockpit ventilation system of a small transport aircraft. The current system does not allow the ECS system to function without activating the main engines, which limits its effectiveness in ground operations. The theoretical part provides a basic theoretical framework for understanding and evaluating the thermal comfort in the cockpit, including heat transfer modes, cabin microclimate during different operating modes, and the definition of fundamental concepts related to ECS in pressurized and non-pressurized cabins. The experimental part focuses on the extension of the system with a suitable electric motor fan to provide cabin air supply even during ground operations at the airport. It includes testing the thermal effect of the supplied untreated air on the human body using a thermal manikin and a cabin simulator. In addition, heat removal from the body surface and subjective thermal sensation at different airflows and outlet routing were investigated for ambient temperature.
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Cooling Concepts in Power Electronics
Hőhn, Matěj ; Súkeník, Jakub (referee) ; Toman, Marek (advisor)
This bachelor thesis deals with cooling concepts in power electronics and experimental measurements of thermal resistances in two different fan-cooled heat sink samples. In the first part of the thesis, calculations of losses in semiconductor switching devices are described. These are losses due to current conduction and switching between operating states. Then the basics of heat transfer theory such as conduction transfer, convection transfer, radiation transfer, and thermal-electrical analogy are described. In the third section, the procedure for calculating the required thermal resistance of the heat sink is described. Then, cooling concepts in power electronics are described, which include basic types of heat sinks, fan-cooled cooling and its operating characteristics, heat pipes, thermoelectric cooling and the use of liquid systems, such as cold plates and boiling liquid cooling. The last part of the thesis describes the preparation of a laboratory workstation for measuring the thermal resistance of two different fan-cooled coolers and comparing the measured results.
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Heat exchanger design for condensing boiler
Plott, Patrik ; Linda, Jakub (referee) ; Baláš, Marek (advisor)
This master's thesis is aimed at the optimization of a gas condensing boiler for domestic heating. The optimization consisted in the design of a new secondary plate heat exchanger for domestic hot water heating using analytical calculation and subsequent CFD simulation of heat transfer and pressure loss. Various designs of plate heat exchangers were proposed. Subsequently, the results of the analytical calculation were compared with the results of the CFD simulation and their mutual conformity with each other was evaluated. After analysing the results of each variant, the proposed plate heat exchanger designs were compared with the currently used heat exchanger. Finally, we identified the best possible solution to replace the current exchanger.
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Flow and heat transfer between the rear side of a turbocharger turbine wheel and the bearing housing
Kalugina, Marina ; Novotný, Pavel (referee) ; Vacula, Jiří (advisor)
The objective of the bachelor’s thesis is to determine the heat balance at the point between the back of the turbine wheel and the bearing housing. The findings concerning the fluid flow and heat transfer in small channels of a rotor-stator system were derived from previously published works. The main focus of this study is the heat exchange between the heated air and the rotor wall. Calculations are applied to the turbine wheel of a real turbocharger to investigate convective heat flow at different local radii. Furthermore, a thermal resistance system is implemented in the stator section to explore potential methods for improving heat dissipation.
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Technology of increasing the efficiency of nuclear power plants
Poláková, Barbora ; Imrichová, Anna (referee) ; Milčák, Pavel (advisor)
This bachelor thesis deals with increasing the efficiency of nuclear power plants, specifically the design of a steam heater. The introduction is devoted to nuclear energy in general, its history, the principle of energy extraction and new nuclear sources in the Czech Republic. The second part focuses on the analysis of the Dukovany nuclear power plant and the possibilities of increasing its efficiency. The third part describes in detail the steam separation and heating technology and its influence on efficiency. In the last two chapters is resented the thermodynamic analysis and the design of the heat exchanger, the aim of which was to determine its length and heat transfer surface.
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Coupled model of synchronous machine
Šmída, Michal ; Kraml, Aleš (referee) ; Vlach, Radek (advisor)
This thesis focuses on creating a coupled model of a synchronous motor using Matlab. To make a coupled model, it is necessary to correctly determine the surrogate schematics that represent the physical domains-electrical, mechanical and thermal. The combination of these parts can be called a coupled model, which captures their interdependence. The main goal of the work is to make the output of the model as close as possible to the real machine.
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Optimization algorithms for inverse heat exchange problems
Ibehej, David ; Dobrovský, Ladislav (referee) ; Kůdela, Jakub (advisor)
This thesis addresses the issue of inverse heat transfer and its solution through optimization. The study focuses on the application of various evolutionary algorithms and their combinations, which are implemented and used to solve the selected problem. In the practical part, models approximating the curve of the material’s effective thermal capacity are designed, and these models are optimized using evolutionary algorithms with the aim of minimizing the difference between simulated and experimental data. Finally, the resulting models and algorithms are compared in terms of their accuracy and efficiency.
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