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Noise reduction oriented optimization of UAV propellers
Ecler, Matěj ; Matějů, Jiří (referee) ; Popela, Robert (advisor)
This diploma thesis deals with optimization of propellers with the aim to reduce their noise level. Based on the measurement of noise level of serial propellers, major propeller noise sources were evaluated. Subsequent 2D simulations of the flow on the individual profiles along the propeller span revealed the locations of separation bubbles, which were identified as a potential source of the noise. Based on these findings, propellers were equipped with turbulator trips of various dimensions and their effect on the noise level and efficiency of the propellers was experimentally verified. The results did not show contribution of turbulator trips to noise reduction or efficiency.
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The influence of sintering schedule on microstructure of advanced ceramic materials with cubic structure
Ecler, Matěj ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
This bachelor thesis deals with the study of the influence of heating schedule on the microstructure of advanced ceramic materials. Relative densities and grain sizes obtained by Single-Step Sintering and Two-Step Sintering were compared. Examined ceramic materials were CeO2, Y2O3 and spinel Al2O3MgO with cubic structure, and TiO2 with tetragonal structure. Only samples of Al2O3MgO and TiO2 achieved relative densities higher than 98%. For those two materials the microstructure was evaluated. The results did not confirm the influence of crystalline lattice symmetry on eciency of Two-Step Sintering.
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Noise reduction oriented optimization of UAV propellers
Ecler, Matěj ; Matějů, Jiří (referee) ; Popela, Robert (advisor)
This diploma thesis deals with optimization of propellers with the aim to reduce their noise level. Based on the measurement of noise level of serial propellers, major propeller noise sources were evaluated. Subsequent 2D simulations of the flow on the individual profiles along the propeller span revealed the locations of separation bubbles, which were identified as a potential source of the noise. Based on these findings, propellers were equipped with turbulator trips of various dimensions and their effect on the noise level and efficiency of the propellers was experimentally verified. The results did not show contribution of turbulator trips to noise reduction or efficiency.
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The influence of sintering schedule on microstructure of advanced ceramic materials with cubic structure
Ecler, Matěj ; Pouchlý, Václav (referee) ; Maca, Karel (advisor)
This bachelor thesis deals with the study of the influence of heating schedule on the microstructure of advanced ceramic materials. Relative densities and grain sizes obtained by Single-Step Sintering and Two-Step Sintering were compared. Examined ceramic materials were CeO2, Y2O3 and spinel Al2O3MgO with cubic structure, and TiO2 with tetragonal structure. Only samples of Al2O3MgO and TiO2 achieved relative densities higher than 98%. For those two materials the microstructure was evaluated. The results did not confirm the influence of crystalline lattice symmetry on eciency of Two-Step Sintering.
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