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Hydrodynamic dampers on the principle of magnetic fluid
Přikryl, Matěj ; Himr, Daniel (referee) ; Pochylý, František (advisor)
This bachelor's thesis deals with damping vibrations emerging due to the movement of a vehicle. The first section provides an overview of contemporary types of dampers with thorough explanation of the principle of hydrodynamic damper. This section also contains simulation of vibrating vehicle equipped with passive damper. Literature research of magnetic fluids and description of magnetoviscous phenomenon is presented in the second part, which freely continues to the topic of magnetorheological (MR) dampers. The final chapter firstly describes current hydrodynamic dampers based on squeeze film (SF) mode of magnetorheological fluid and at the conclusion the author's concept of SF MR damper is submitted.
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Measurements of the stress in the turbine spiral casing using the strain gauges
Dokoupil, Pavel ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The Master‘s thesis is focused on measuring of the stress in the spiral case of water turbine using the strain gauges measurement. It contains the theoretical and the practical part. The theoretical part includes a description of theoretical background (basic mechanics, measurement and evaluation, strain gauges, pressure measurement, uncertainty of measurement). One of the chapters describes Water Power Plant Lipno nad Vltavou (history of power plant, issues and the history of measurement). The practical part contains a theoretical calculation of measurement uncertainty and measuring of stress on spiral case Francis turbine at Water Power Plant Lipno I (Unit TG2). Measurement was made before and after overhaul. There are described technical data of spiral cases, description of measurement, results of measuring of strain and stress including comparison with the pressure in spiral case and calculation of uncertainties of measurement.
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Using generalized functions in continuum mechanics
Procházka, Petr ; Netuka, Horymír (referee) ; Pochylý, František (advisor)
Tato práce se zabývá využitím distribucí neboli zobecněných funkcí k řešení nestacionárních okrajových problémů v mechanice kontinua. Nejprve je zavedena teorie distribucí a jejich definice jako spojitých lineárních funkcionálů na prostoru testovacích funkcí. Druhá část teoretické kapitoly představuje Laplaceovu integrální transformaci. Následující kapitola se věnuje řešení průhybu nosníků pod vlivem nespojitého časově proměnlivého zatížení. Jejím výsledkem je vytvoření obecného modelu řešení průhybových čar nosníků vužitím distribucí. Poslední kapitola se zabývá řešením nestacionárního proudění v trubicích spojených hydraulickými prvky.
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Valveless Plunger Pump
Machů, Tomáš ; Kozubková, Milada (referee) ; Melichar, Jan (referee) ; Pochylý, František (advisor)
This thesis deals with valveless reciprocating pumps. Within the thesis several designs of pump geometry are demonstrated. Their parameters were obtained using computational fluid dynamics. Reciprocating piston movement was simulated by time dependent inlet boundary condition or by dynamic mesh. The individual variants were compared mainly from point of view of volumetric efficiency, which was the main evaluated parameter. Results of calculations are presented as dependencies of volumetric efficiency on frequency and amplitude of piston motion and on value of backpressure. Two variants of the prototype pump geometry were manufactured to experimentally validate parameters obtained from calculations. Volumetric efficiency together with hydraulic efficiency were evaluated from measured data.
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Dynamic behavior od rotor dynamics stystem vibrating in a liquid
Chlud, Michal ; Pochylý, František (referee) ; Malenovský, Eduard (advisor)
This thesis deals with dynamic behavior of swirl turbine vibrating in a liquid. Primarily is studied decrease of natural frequencies of rotor due the interaction with fluid environment, namely for different levels of submerged rotor in fluid. After that follows the detection of natural frequencies of swirl turbine in operating speed. The problem is solved by computational modeling in ANSYS system. For this solution is used acoustic elements method. The results are compared with experiment.
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Self-priming pump
Urban, Jiří ; Hudec, Martin (referee) ; Pochylý, František (advisor)
Diploma thesis is focused on self-priming pump 25 - OVE Sigma pumpy Hranice s.r.o., for its function is essential the ejector which is placed in the body of the pump. On the basis of the results of measurements there are designed construction modifications using a mathematical model. For the first time were made measurements to verify the self-priming capability with determining the maximum suction height.
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