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Výpočet tepelného odporu žebrovaného chladiče
Kyanka, Radim ; Huták, Petr (oponent) ; Toman, Marek (vedoucí práce)
Tato bakalářská práce je zaměřena na problematiku výpočtu analytických vztahů potřebných na definování tepelných odporů žebrovaných chladičů. Nejprve je popsáno, jak probíhá teplota při různých okrajových podmínkách na konci žebra. Poté popisuje mechanismy přestupu tepla, výpočty tepelných odporů obzvlášť u přirozené a nucené konvekce. Pro ověření jsou provedeny porovnání mezi výpočty pomocí analytických vztahů obsaženy v programu Matlab a výsledky z praktického měření.
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High Voltage Switchgear Thermal Distribution Analysis
Bílek, Tomáš ; Rudolf, Pavel (oponent) ; Hrabovský, Jozef (vedoucí práce)
This thesis deals with analysis of thermal field inside high voltage switchgear cabin. It de-scribes applied methodology based on combination of CFD simulation of air flow inside switch-gear cabin and series of experimental measurements. Based on results for reference geometry it provides proposals of switchgear layout modification to decrease temperature rise on switch-gear critical components during its operation. In the second part of this thesis problem of bus-bar joints is discussed. Busbar joints are one of the key thermal sources inside switchgear cab-in. Statistical method of design of experiment is applied for experimental investigation of bus-bar joint temperature rise. Results from design of experiment are supported by finite element simulation of contact in busbar joint.
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Helium Cryostat for Experimental Study of Natural Turbulent Convection
Urban, Pavel ; Jícha, Miroslav (oponent) ; Rotter, Miloš (oponent) ; Fedor,, Ján (oponent) ; Musilová, Věra (vedoucí práce)
The thesis focuses on the design of a helium cryostat with an experimental convection cell for the study of natural turbulent convection in the range of Rayleigh numbers Ra up to 1015 and Nusselt numbers Nu up to 104. Cryogenic 4He gas is used as a working fluid for experimental studies due to its advantageous properties that allow reaching very high Ra numbers. The cryostat design is based on the conception of low-loss NMR magnet cryostats. In the centre of the cryostat a cylindrical convection cell of 300 mm in diameter and 300 mm in height is placed. The cell is made of middle, top and bottom parts. These are jointed together by flanges sealed by indium wires. The middle part is exchangeable and allows the geometry of the cell to be modified. The cell is designed for measurements at pressures up to 250 kPa. The main advantage of this cryostat is the minimal influence of the cell design and materials on the studied convection.
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Výpočet tepelného odporu žebrovaného chladiče
Kyanka, Radim ; Huták, Petr (oponent) ; Toman, Marek (vedoucí práce)
Tato bakalářská práce je zaměřena na problematiku výpočtu analytických vztahů potřebných na definování tepelných odporů žebrovaných chladičů. Nejprve je popsáno, jak probíhá teplota při různých okrajových podmínkách na konci žebra. Poté popisuje mechanismy přestupu tepla, výpočty tepelných odporů obzvlášť u přirozené a nucené konvekce. Pro ověření jsou provedeny porovnání mezi výpočty pomocí analytických vztahů obsaženy v programu Matlab a výsledky z praktického měření.
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Helium Cryostat for Experimental Study of Natural Turbulent Convection
Urban, Pavel ; Jícha, Miroslav (oponent) ; Rotter, Miloš (oponent) ; Fedor,, Ján (oponent) ; Musilová, Věra (vedoucí práce)
The thesis focuses on the design of a helium cryostat with an experimental convection cell for the study of natural turbulent convection in the range of Rayleigh numbers Ra up to 1015 and Nusselt numbers Nu up to 104. Cryogenic 4He gas is used as a working fluid for experimental studies due to its advantageous properties that allow reaching very high Ra numbers. The cryostat design is based on the conception of low-loss NMR magnet cryostats. In the centre of the cryostat a cylindrical convection cell of 300 mm in diameter and 300 mm in height is placed. The cell is made of middle, top and bottom parts. These are jointed together by flanges sealed by indium wires. The middle part is exchangeable and allows the geometry of the cell to be modified. The cell is designed for measurements at pressures up to 250 kPa. The main advantage of this cryostat is the minimal influence of the cell design and materials on the studied convection.
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High Voltage Switchgear Thermal Distribution Analysis
Bílek, Tomáš ; Rudolf, Pavel (oponent) ; Hrabovský, Jozef (vedoucí práce)
This thesis deals with analysis of thermal field inside high voltage switchgear cabin. It de-scribes applied methodology based on combination of CFD simulation of air flow inside switch-gear cabin and series of experimental measurements. Based on results for reference geometry it provides proposals of switchgear layout modification to decrease temperature rise on switch-gear critical components during its operation. In the second part of this thesis problem of bus-bar joints is discussed. Busbar joints are one of the key thermal sources inside switchgear cab-in. Statistical method of design of experiment is applied for experimental investigation of bus-bar joint temperature rise. Results from design of experiment are supported by finite element simulation of contact in busbar joint.
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