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Optimization of the siphon swirl turbine draft tube
Mach, Jiří ; Haluza, Miloslav (referee) ; Rudolf, Pavel (advisor)
The goal of this diploma thesis is to design a new shape of the draft tube, which will be easier to manufacture while maintaining good strength and hydraulic properties. First part of this thesis is devoted to the formulation of the problem, description of the swirl turbine, principle of operation, the basic variants of arrangement, also the function of the draft tube, its efficiency and other formulas. In the second part of this thesis is a CFD and strength analysis of the original design, also a new design is proposed and the possibility of optimization using ANSYS Fluent Adjoint solver.
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The computation of draft tobe of the turbine for giving parameters
Žák, František ; Veselý, Jindřich (referee) ; Haluza, Miloslav (advisor)
This diploma thesis describes design of a new shape of the draft tube for small hydro Katovice with maintaining built dimension. First part of this thesis is devoted to the formulation of the problem, description of basic function of the draft tube, its efficiency and other formulas. In the second part of this thesis the analysis is made for original design supported by CFD calculation. Furthermore a new design of the draft tube is made with comparison of original draft tube.
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Flow control in a hydraulic turbine draft tube
Litera, Jiří ; Štefan, David (referee) ; Rudolf, Pavel (advisor)
Hydraulic energy is one of the most important sources in the world for electricity production. Nowadays the trend is to limit the production of the electricity from fossil fuels and to protect the environment. The main idea is to use more renewable energy sources such as wind and solar energy. Unfortunately, these alternative sources are strongly dependent on current weather conditions, which causes the instability of the electrical grid. Luckily pumped storage and hydraulic power plants provide the solution. However, it requires an extension of the operating range of the hydraulic machines. For that reason, the water turbines now operate over and extended range of regimes, that can be quite far from the best efficiency point. Hence two types of unstable two-phase flows in the Francis turbine draft tube occur: part load overload. This diploma’s thesis is focused on the Francis turbine operating at the part load. During part load conditions the helical vortex rope is being developed in the draft tube, it causes pressure pulsation and it can lead to the hydro-acoustic resonance, which damages the elements of the power plant. The aim is to eliminate the pulsation by jet control of the swirling flow in the draft tube. In the diploma’s thesis, various approaches to jet control of the flow in conical diffuser are tested using the computational fluid dynamics.
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Contradictions analysis of small water power Ostravice.
Kupčík, Roman ; Skoták, Aleš (referee) ; Haluza, Miloslav (advisor)
The main subject of the diploma thesis „Contradiction analysis of small water power Ostravice“ is solution of reduced output of small water power plant on the river Ostravice near the town Vratimov. Power plant equippment is axial flow Kaplans turbine RA – 3,5 – 0 1000 with runner diametr 1000 mm. Low output is caused by draft tube. New draft tube is designed in this masters thesis. For hydraulic layout was used CFD software Fluent. The aim of this work is finding of optimal shape which leads to increasing of power from current 30 kW to projected 55 kW.
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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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The runner for the straight-flow turbine for small hydro power Sobotín
Žižka, Jakub ; Veselý, Jindřich (referee) ; Haluza, Miloslav (advisor)
The thesis deals with the problem of optimizing an existing unused turbine for use in a different location than the designed. The goal is to reduce the flow through the turbine by changing the runner geometry while increasing the head, with the least possible decrease in efficiency. The individual modifications of the hydraulic shape are based on the knowledge of the basic relations for the designing of hydrodynamic machines. Numerical fluid mechanics is a tool for validating the effect of individual adjustments. The hydraulic design of the new runner and draft tube of the axial propeller turbine with a fixed guide vanes is performed. Based on the CFD simulation, a universal turbine characteristic with a new hydraulic shape is compiled.
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Vortex rope for overload operation of Francis turbine
Kozák, Jiří ; Štefan, David (referee) ; Rudolf, Pavel (advisor)
This master's thesis deals with CFD simulation of vortex rope in the elbow draft tube for overload operation of Francis turbine. The main objective of the thesis is to compare results of the CFD simulations of the original elbow draft tube with a derived straight cone draft tube considering volume and the shape of the cavitation region and dynamic flow characteristic. Results of the 3D simulations are also compared with axi-symmetric simulations, which reduce demands for computing time and power.
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CFD simulation of vortex structure in the Francis turbine draft tube at part load operating point - comparison with measurements
Neděla, Jiří ; Urban, Ondřej (referee) ; Štefan, David (advisor)
This master's thesis deals with simulation of vortex structure which is created in the draft tube of Francis turbine, at part load flow conditions. The main objective is to get the most accurate results from the calculations, using the student license of Ansys Fluent 19.1. The results from the calculations are compared with the experiment under the Francis-99 project. Mainlly in terms of dynamic properties of vortex rope – aplitude and frequency of pressure pulsations. Additionaly the time-averaged velocity profiles are compared. I used the test-case provided by NTNU – Norwegian University of Science and Technology under the Francis-99 workshop series.
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