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Extrapolation of diagrams of resistance coefficients using virtual experiment
Koreň, Denis ; Vondál, Jiří (oponent) ; Juřena, Tomáš (vedoucí práce)
As a part of pneumatic breaking systems, disc valves are used for very small actuations of the valves, for which no values for pressure losses are found in literature. The correct design shall be made conditional on the total pressure loss of system, a part of which also occurs in the flow of the given valve. The work is initially devoted to a description of the calculation of the resistance coefficient and the characteristics of the physical processes during the flow in the idealized valve. Consequently, design of the model for the flow at the entrance into the valve end at the exit from the valve, including the setting of the simulations in the Fluent, is clarified. An important part of the work are sensitivity tests of the model to Reynolds number, to the model of turbulence and the mesh resolution near the wall. In addition, the results of simulations for various relative scales of the model are compared with experimental data given in the literature. The outputs of the work are the resistance coefficients, which extrapolate the data in the available resources, especially for valves with small relative actuation (h/Dh
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Flue gas condensation in a domestic wood pellet boiler
Koreň, Denis ; Jecha, David (oponent) ; Juřena, Tomáš (vedoucí práce)
The diploma thesis deals with the analysis of flue gas condensation with the possibility of using flue gas humidification in a domestic wood pellet boiler. The review is focused on flue gas humidification in condensing solid fuel boilers and on water vapour condensation in the presence of non-condensable gases. A description of the wood pellet boiler with balance calculations of flue gas temperature and composition is given. The flue gas condensation in the boiler heat exchanger section is analysed on a CFD model developed in ANSYS Fluent. Experimental measurement data are used to validate the developed model. The CFD simulations are evaluated with respect to heat transfer and flue gas condensation rate. The effect of turbulators and flue gas humidification is taken into account. The thesis concludes with an evaluation of flue gas humidification in solid fuel boilers in terms of thermal efficiency, reduction of particulate emissions in the flue gas and boiler design.
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Extrapolation of diagrams of resistance coefficients using virtual experiment
Koreň, Denis ; Vondál, Jiří (oponent) ; Juřena, Tomáš (vedoucí práce)
As a part of pneumatic breaking systems, disc valves are used for very small actuations of the valves, for which no values for pressure losses are found in literature. The correct design shall be made conditional on the total pressure loss of system, a part of which also occurs in the flow of the given valve. The work is initially devoted to a description of the calculation of the resistance coefficient and the characteristics of the physical processes during the flow in the idealized valve. Consequently, design of the model for the flow at the entrance into the valve end at the exit from the valve, including the setting of the simulations in the Fluent, is clarified. An important part of the work are sensitivity tests of the model to Reynolds number, to the model of turbulence and the mesh resolution near the wall. In addition, the results of simulations for various relative scales of the model are compared with experimental data given in the literature. The outputs of the work are the resistance coefficients, which extrapolate the data in the available resources, especially for valves with small relative actuation (h/Dh
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