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Utilization of hydrodynamic cavitation for water treatment
Balko, Marek ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with the observation of features of cavitation with emphasis on the hydrodynamical cavitation and its use for eliminating unwanted and badly degradable compounds from water. Thanks to high temperature and pressures that are present at a colapse of cavitation bubbles the water decomposes into highly reactive hydroxile radicals which are able to decompose even. This effect can furthermore be strenghtened by the use of advanced oxidation processes – AOP. The experimental part of thesis is dedicated to examining a ability of hydrodynamical cavitation degrade particular chemical substance from water, namely estrogen.
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Study of heat transfer by turbulent flow in cold helium gas in experiment with Rayleigh-Bernard convection at ISI CAS in Brno
Balko, Marek ; Štigler, Jaroslav (referee) ; Macek, Michal (advisor)
The diploma thesis deals with the study of Rayleigh-Bénard convection for Rayleigh numbers in the range 1E8-1E14. The evaluated data come from an experiment with cryogenic helium in a cylindrical cell in a configuration with cell diameter D = 30 cm, height L = 30 cm and a second configuration with cell diameter D = 30 cm, height L = 15 cm. Miniature sensors recorded temperature fluctuations over time under various physical conditions and properties of helium. Using MATLAB software, the output parameters of the system (Nusselt and Reynolds numbers) and their dependence on the control parameters (Rayleigh and Prandtl numbers) were determined from the measured data. A new approach to the distribution of measured signals according to the direction of large scale circulation was used in the work, which leads to improved analysis. Reynolds numbers were evaluated using the so-called elliptic method. Furthermore, the work deals with the study of the coherent structure of the large scale circulation inside the cell.
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Venturi nozzle shape influence on hydrodynamic cavitation
Mračko, Patrik ; Balko, Marek (referee) ; Rudolf, Pavel (advisor)
Thesis focuses on the influence of various differently shaped diffusers of Venturi nozzle on the cavitation, which occurs during flow of liquid through said nozzle. Several models with different shapes of diffuser's wall were designed. Cavitation in these models was then investigated with numerical calculation. Two physical nozzles were made according to designed models and tested on experimental circuit. As part of the experiment, the cavitation inside the nozzles was measured with flow of liquid corresponding to a large range of cavitation numbers. Results of this experiment were used to determine which model of the nozzle is more effective in creation of a cavitating flow.
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Car chassis diffuser
Kindl, Albert ; Balko, Marek (referee) ; Rudolf, Pavel (advisor)
Improving a car's aerodynamic properties can save fuel, increase range, or improve speed and handling. To achieve this, aerodynamic modifications and improvements are proposed to cars. The aim of this thesis is to describe a diffuser on an automotive chassis. The focus is mainly on the effect of its divergence angle on drag and lift. These dependencies are investigated on a simplified car model using CFD simulation in Ansys Fluent. The research section discusses the diffuser flow and losses, other important aerodynamic features and the importance of the diffuser in Formula 1 and passenger cars. The results of the thesis show the significant effect of the diffuser on the downforce and drag of the vehicle and indicate the important position of this element in the future of the automotive industry.
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Venturi nozzle shape influence on hydrodynamic cavitation
Mračko, Patrik ; Balko, Marek (referee) ; Rudolf, Pavel (advisor)
Thesis focuses on the influence of various differently shaped diffusers of Venturi nozzle on the cavitation, which occurs during flow of liquid through said nozzle. Several models with different shapes of diffuser's wall were designed. Cavitation in these models was then investigated with numerical calculation. Two physical nozzles were made according to designed models and tested on experimental circuit. As part of the experiment, the cavitation inside the nozzles was measured with flow of liquid corresponding to a large range of cavitation numbers. Results of this experiment were used to determine which model of the nozzle is more effective in creation of a cavitating flow.
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Study of heat transfer by turbulent flow in cold helium gas in experiment with Rayleigh-Bernard convection at ISI CAS in Brno
Balko, Marek ; Štigler, Jaroslav (referee) ; Macek, Michal (advisor)
The diploma thesis deals with the study of Rayleigh-Bénard convection for Rayleigh numbers in the range 1E8-1E14. The evaluated data come from an experiment with cryogenic helium in a cylindrical cell in a configuration with cell diameter D = 30 cm, height L = 30 cm and a second configuration with cell diameter D = 30 cm, height L = 15 cm. Miniature sensors recorded temperature fluctuations over time under various physical conditions and properties of helium. Using MATLAB software, the output parameters of the system (Nusselt and Reynolds numbers) and their dependence on the control parameters (Rayleigh and Prandtl numbers) were determined from the measured data. A new approach to the distribution of measured signals according to the direction of large scale circulation was used in the work, which leads to improved analysis. Reynolds numbers were evaluated using the so-called elliptic method. Furthermore, the work deals with the study of the coherent structure of the large scale circulation inside the cell.
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Utilization of hydrodynamic cavitation for water treatment
Balko, Marek ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with the observation of features of cavitation with emphasis on the hydrodynamical cavitation and its use for eliminating unwanted and badly degradable compounds from water. Thanks to high temperature and pressures that are present at a colapse of cavitation bubbles the water decomposes into highly reactive hydroxile radicals which are able to decompose even. This effect can furthermore be strenghtened by the use of advanced oxidation processes – AOP. The experimental part of thesis is dedicated to examining a ability of hydrodynamical cavitation degrade particular chemical substance from water, namely estrogen.
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