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Modal Analysis of the Swirl Turbine Rotor Blades
Pekar, Marek ; Chromek, Lukáš (referee) ; Lošák, Petr (advisor)
The aim of this diploma thesis is to determine and compare modal properties of four swirl turbine wheels, each with a different geometry. Natural frequencies and mode shapes were obtained based on computer modelling using Ansys software and they were compared with experimental modal analysis' results. The computer modelling and the experimental modal analysis were carried out for different boundary conditions and in different environments. The beginning of the thesis is dedicated to a brief overview of literature with similar issues. Then a brief introduction of a dynamics theory is mentioned in which equations of motion for a damped and an undamped single degree of freedom system are derived. The creation of a geometry model which is obtained by a reverse engineering is shown in the second part of the thesis. The geometry model was subsequently used for the computer based modelling of the modal parameters. In the third part an experimental equipment, setting, measurement and processing of data are described. The conclusion of the thesis is dedicated to the comparison of the results obtained by the experimental modal analysis and the computing modelling is presented. Moreover, influence of boundary conditions and influence of the environment on the natural frequencies are evaluated.
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Analysis of pulse wave propagation in aorta
Tichoň, Dušan ; Klas, Roman (referee) ; Burša, Jiří (advisor)
The aim of this diploma thesis is to assess the applicability of pulse wave propagation monitoring in the cardiovascular system in the field of prediction and early diagnosis of abdominal aortic aneurysm (AAA). The very first part is focused on description of heart and blood vessels with its pathological changes in presence of aneurysm. For this reason, current methods of monitoring and surgical treating of AAA were mentioned. Due to their difficult clinical use widely in the population, new methods based on pulse wave monitoring were presented. Using an analytical approach we estimated the difference in the arrival of the pulse wave at measurable locations between healthy and pathological aorta in the order of miliseconds. By experimental monitoring using photoplethysmographic sensors, we observed significant changes of pulse wave velocity with respect to the mechanical properties of the artery wall (mainly associated with age), which we tried to implement by hyperelastic material models used in computational simulations of pulse wave proagation on simplified geometries by fluid structure interaction method. These analyzes should verify applicability of FSI simulations in further development of diagnostic methods of AAA.
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Analysis of pulse wave propagation in aorta
Tichoň, Dušan ; Klas, Roman (referee) ; Burša, Jiří (advisor)
The aim of this diploma thesis is to assess the applicability of pulse wave propagation monitoring in the cardiovascular system in the field of prediction and early diagnosis of abdominal aortic aneurysm (AAA). The very first part is focused on description of heart and blood vessels with its pathological changes in presence of aneurysm. For this reason, current methods of monitoring and surgical treating of AAA were mentioned. Due to their difficult clinical use widely in the population, new methods based on pulse wave monitoring were presented. Using an analytical approach we estimated the difference in the arrival of the pulse wave at measurable locations between healthy and pathological aorta in the order of miliseconds. By experimental monitoring using photoplethysmographic sensors, we observed significant changes of pulse wave velocity with respect to the mechanical properties of the artery wall (mainly associated with age), which we tried to implement by hyperelastic material models used in computational simulations of pulse wave proagation on simplified geometries by fluid structure interaction method. These analyzes should verify applicability of FSI simulations in further development of diagnostic methods of AAA.
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Modal Analysis of the Swirl Turbine Rotor Blades
Pekar, Marek ; Chromek, Lukáš (referee) ; Lošák, Petr (advisor)
The aim of this diploma thesis is to determine and compare modal properties of four swirl turbine wheels, each with a different geometry. Natural frequencies and mode shapes were obtained based on computer modelling using Ansys software and they were compared with experimental modal analysis' results. The computer modelling and the experimental modal analysis were carried out for different boundary conditions and in different environments. The beginning of the thesis is dedicated to a brief overview of literature with similar issues. Then a brief introduction of a dynamics theory is mentioned in which equations of motion for a damped and an undamped single degree of freedom system are derived. The creation of a geometry model which is obtained by a reverse engineering is shown in the second part of the thesis. The geometry model was subsequently used for the computer based modelling of the modal parameters. In the third part an experimental equipment, setting, measurement and processing of data are described. The conclusion of the thesis is dedicated to the comparison of the results obtained by the experimental modal analysis and the computing modelling is presented. Moreover, influence of boundary conditions and influence of the environment on the natural frequencies are evaluated.
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