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Elements reducing pressure in pipeline systems
Kohút, Jiří ; Kůrečka, Jan (referee) ; Himr, Daniel (advisor)
The aim of the bachelor thesis is to provide a comprehensive overview of control elements in piping systems. The fluid at different flow rates exhibits different behavior and due to the fluid contact with the pipeline, pressure losses occur. Elements in piping systems meet various requirements such as pressure control, flow rate control, barrier and flow direction control. The thesis deals with the categories description and functional priciples of individual elements. The practical part consists of the laboratory measurement describing characteristic of one of the pressure control elements, namely the pressure reducing valve. The measured characteristic is compared to characterstic from a company called Malgorani.
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Unsteady flow in pipeline
Šrenk, David ; Fialová, Simona (referee) ; Himr, Daniel (advisor)
The thesis deals with unsteady flow in the pipeline. Only one component of velocity is dominant in piping, so the problem is simplified to one-dimensional. Bachelor thesis has an analytical basis in partial differential equations of hyperbolic type. The problem and types of numerical methods are also numerically described. The numerical methods describe the boundary conditions and properties of the given methods.
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Air valve as protection from water hammer
Sedlmajer, Jakub ; Machů, Tomáš (referee) ; Himr, Daniel (advisor)
The thesis deals with air valves, focusing on vacuum air valves. The theoretical part describes basic water hammer theory, especially low pressure problematics. Subsequently there are briefly explained any of usual water hammer protections, air valves function principles and differences in vacuum air valves constructions. The work is finished by measurement which evaluates reduction of pressure head according to use of this kind of protection.
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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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Modelling of pressure pulsations in pipes
Hofírek, Michal ; Havlásek, Michal (referee) ; Himr, Daniel (advisor)
This diploma thesis deals with problem of water hammer in pipes affected by viscoelastic behavior of pipe material. Mathematical model uses pressure dependent speed of sound in water air mixture. For purpose of numerical solution the Method of Characteristics with independent time step is introduced. This method is compared with commonly used methods such as Method of Characteristics (MOC) and Lax Wendroff scheme. Derived model, solved with Method of Characteristics with independent time step, is verified with experimental simulation.
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Measurement of dynamic characteristic of check valves
Novák, Jan ; Himr, Daniel (referee) ; Habán, Vladimír (advisor)
Master thesis presents overview of existing types of check valves, their features, uses and issue called "cracking". Experimental part of this thesis focuses on the lift and swing check valves. Results of the measurement are evaluated from non-stationary flow point of view by developing and analyzing static and dynamic characteristics. This thesis takes into account losses and dynamic effects as main viewpoints. Two methods for measuring non-stationary velocities are used. Direct method called Gibson and indirect method laser doppler anemometry. Goal of the master thesis is to increase understanding of the check valves and their applicability.
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Usage of Fluent in computations of unsteady flow in large networks
Pavelka, František ; Štefan, David (referee) ; Himr, Daniel (advisor)
The main objective of this Master´s thesis is the appropriate calculation proposal of pressure and discharge conditions in extensive ducts in unsteady flow. The calculation proposal was aimed at the conenction of two commercial programmes. Exacly the programme Ansis Fluent and Matlab, which deals with the connection of onedimensional (1D) calculation in Matlab and multidimensional (2D) calculation in Ansys Fluent programme. This Mastr’s thesis also deals with creation of the independent 1D model (Matlab, method of characteristic) and independent 2D model flow (Ansys Fluent, Inviscid model).
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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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Solution of Non-Linear Hydraulic Networks
Himr, Daniel ; Kozubková, Milada (referee) ; Šklíba, Jan (referee) ; Abaid, Emhemmed (referee) ; Pochylý, František (advisor)
Thesis deals about solution of non-steady flow in hydraulic systems, which have one dominant component of velocity. Such systems can be arbitrarily structured and they are not limited by number of elements. Computation is based on Lax-Wendroff method and enables considering of variable sound peed as function of static pressure and properties of pipe material. It means, that hydraulic system can be very various. Numerical method is described in detail and description is also focused on sensitivity of method for time step and length step. It can be very imported for evaluation of numerical viscosity, which is compared with second viscosity of fluid. Hammer is working title of software, which was developed on the basis of written numerical procedures. This software enables fast computation of flow in pipe-line systems.
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