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Determination of check valve dynamic properties
Dolníček, Petr ; Habán, Vladimír (referee) ; Himr, Daniel (advisor)
One of the objectives of the master´s thesis is to summarize types of most used check valves and their constructions. These check valves have specific static and dynamic properties. One of dynamic properties is vibration of closing member of lift check valve. Due to these vibrations, the added effects of fluid may result. This thesis deals with explanation and computation of these added effects.
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Numerical model of air valve
Luňák, Pavel ; Štigler, Jaroslav (referee) ; Himr, Daniel (advisor)
This diploma thesis deals the formation of water hammer in pipes and the suppress the nega-tive effects especially for the use of protective devices (surge tank, air chamber, air valve and other). The special attention is paid to the use of the air valve, for which it was developed mathematical model. The solution is based on the use of numerical methods Lax-Wendroff with boundary conditions for the air valve.The numerical results are confronted with the ex-periment in conclusion.
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Determination of the working range and efficiency of the water hammer pump
Růžička, Jakub ; Himr,, Daniel (referee) ; Špano, Miroslav (advisor)
This thesis focuses on setting the range and efficiency of a water ram pump through experimental measurements in a laboratory. The measurements were carried out on three different constructions of water ram pump, each of the designed and assembled by the author of this thesis himself, to find out whether the weight on the pulsating valve has an influence on the water ram pump efficiency. Further on this thesis aims at the comparison of up to now methods of water transport arrangement used at a summer camp and the usage of the water ram pump and its advantages. The principal of water ram pump originates in hydraulic impact that is being precisely described in a great detail as well. On of the chapters even includes the placement manual for the water ram pump and its overall assembly and connexion. Because the presence of floating debris is inevitable, this thesis also deals with the possibility to solve the incoming water impurities by adding an inflow gating to prevent such problem. This inflow gating has only been designed in a Flow 3D programme to introduce the idea and functions.
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Properties of fluids
Dzjamko, Vladislav ; Štefan, David (referee) ; Himr, Daniel (advisor)
The aim of this thesis is to present the basic equations describing the behaviour of fluids and to describe the substance characteristics that are present in them. The thesis is divided into four successive chapters, the first two of which explain the causes and consequences of the various fluid properties. The following chapter is devoted to equations and their derivation. Finally, the content of the thesis includes a description of some methods for determining selected material constants.
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Pump design
Čejka, Pavel ; Himr, Daniel (referee) ; Klas, Roman (advisor)
In this bachelor’s thesis are including basic information about dividing hydrostatic pump. In the first chapter of thesis will be introduced the basic dividing pumps namely on pump hydrostatic and hydrodynamic. Accordance with this dividing will be next introduced basic construction design of hydrostatic pump. With each one type of pump will be introduced their advantages and disadvantages, then also their description of function and their using in practice and all this will be eked with simple scheme or with picture of pumps. Next will be described individual characteristic parts of their construction. In the conclusion will be introduced basic numerical relations for characteristic value of pump and their interdependence will be described with diagrams.
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Pressure surge in the flowing gas simulation
Sedlmajer, Jakub ; Himr, Daniel (referee) ; Habán, Vladimír (advisor)
Creation of vacuum is very slow, energetically and technologicaly demanding process. Closing of valve is very simple and fast process which produces pressure surges when moving cylinder of fluid is stopped. The goal of this thesis is to find out, if it is possible to combine these processes. To reach this goal, 1D model of compressible gas flow and pressure surges in direct pipeline was made. Then follows experimental measurement evaluation and assessment of potential that the technology offers.
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Draft tube role in hydraulic turbine performance
Havlát, Pavel ; Himr, Daniel (referee) ; Rudolf, Pavel (advisor)
This bachelor’s thesis deals with the problems of draft tube. It contains basic description of draft tubes, their division and possibilities of their utilizations. Further, this thesis focuses on description of draft tubes, their efficiency, losses and ways to eliminate these losses. One part of this work also mentions basic relationships required for computing length of draft tube, velocity of the fluid in the draft tube and others.
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Numerical solution of the cavitation bubble dynamics
Münster, Filip ; Himr, Daniel (referee) ; Rudolf, Pavel (advisor)
This thesis deals with the numerical solution of cavitation bubble dynamics and with cyanobacteria gas vesicle behaviour. A program for the numerical calculation of bubble dynamics is created using the Rayleigh-Plesset equation and its modifications. Subsequently, bubbles of different sizes are investigated during acoustic cavitation with various driving frequencies. Furthermore, a model for hydrodynamic cavitation is created. The model combines CFD computation of flow in the Venturi nozzle with the cavitation bubble dynamics calculation. The last part of the work is dedicated to cyanobacteria gas vesicle behaviour in a variable pressure field and during passage through the Venturi nozzle.
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Water turbines and them use
Machát, Pavel ; Sloupenský, Zdeněk (referee) ; Himr, Daniel (advisor)
This bachelor´s thesis deals with the problems of water turbines. It contains basic division of water turbines, description of their oparations and possibilities of their utilizations. Further this thesis focuses on description of the three most used turbines i.e. Francis´s, Kaplan´s and Pelton´s turbines. As one component of this work there are also mentioned essential relations required for selection of proper type of turbine in dependency on speed, slope and flow rate.
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Sensitivity analysis of pressure-time method on measurement uncertainty
Červinková, Kateřina ; Himr, Daniel (referee) ; Habán, Vladimír (advisor)
The pressure-time method is one of two methods of measuring the flow rate on large hydraulic structures applicable to IEC 60041, which is based on the temporal integration of the measured pressure difference and the formation of a water hammer in a closed pipe. The aim of this master thesis is to perform a literature review of this method and to evaluate the flow rate of the measured data. Furthermore, the thesis deals with determination of the sensitivity of the evaluated flow rate to the weights of individual pressure sensors and to numerical modifying of the measured pressures. The first part is made using MS Excel. The flow rate is always evaluates with only one pressure sensor and it is compared with the original flow rate. There is research, how absence of the sensor has an impact on the evaluated flow rate. In the second part of the determination of the sensitivity of the evaluated flow rate, various encroachment (signal smoothing, noise, time delay, frequency band removal) are performed of measured pressure signal in Matlab. Various surrounding influences or sensors failures are simulated.
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