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Hydraulic turbine diffuser optimization using adjoint solver
Pham, Jakub ; Štefan, David (referee) ; Rudolf, Pavel (advisor)
Tato práce se zabývá tvarovou optimalizací difuzoru vírového generátoru, který napodobuje oběžné kolo Francisovy turbíny. Optimalizace je založena na použití adjoint řešiče v programu ANSYS Fluent. Hlavním cílem bylo potlačení vírového copu v mimooptimálních režimech. Byla vytvořena metodika iterativní optimalizace pro adjungovaný řešič. Cílová funkce pro adjungovaný řešič byla zvolena s cílem minimalizovat moment hybnosti proudění kolem osy difuzoru. Byl představen a analyzován nový návrh difuzoru. Poté bylo provedeno srovnání chování vírového copu a proudového pole uvnitř nového a starého návrhu difuzoru. Bylo zjištěno, že optimalizace tvaru nevedla k žádnému významnému zlepšení chování vírového copu, přičemž energie vírového copu se pouze přenesla dále od náboje vírového generátoru. V závěru této práce byla formulována doporučení pro budoucí metody zmírnění vírového copu.
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Hydraulic solution of the swirl turbine for locality of Rosenauer mill
Pavlíček, Tomáš ; Veselý, Jindřich (referee) ; Haluza, Miloslav (advisor)
This thesis focuses on the design of a swirl turbine for the site of Rosenauer Mill, where the gross hydraulic head HB is 1 m and the flow rate is Q is 1.6 m3/s. The beginning of the work is dedicated to microturbines and explains why a swirl turbine is suitable for this location. The procedure applied for developing the hydraulically active surfaces of the turbine is then presented. Firstly the design of the blades is based on analytical formulas, which are further refined using the CFX Ansys program. The turbine is closely affected by the inlet and draft tube, therefore their design is also included in this thesis. The hydraulic calculations yield the resulting parameters and characteristics of the designed turbine, calculated from the entire assembly using CFD computations. The final section of the work is devoted to the design of main structural components such as the gear, shaft, and bearings. The hydraulic design developed in this thesis serves as the basis for implementing the swirl turbine and constructing a small hydraulic power plant at the Rosenauer Mill.
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Study of the Dissipation in Spiraling Vortical Structures
Štefan, David ; Drábková, Sylva (referee) ; Koutník,, Jiří (referee) ; Skoták, Aleš (referee) ; Rudolf, Pavel (advisor)
This work deals with study of swirling flows where the spiral vortical structure appears. The main relation is to flow seen in the draft tube cone of hydraulic turbines operated out of the design point (i.e. best efficiency point). In this cases large coherent vortex structure (vortex rope) appears and consequently high pressure pulsations are propagated to the whole machine system leading to possible restriction of turbine operation. This flow features are consequence of flow instability called vortex breakdown in case of Francis turbine operated at part load (flow rate lower than optimal one). The present study is carried out using simplified device of swirl generator in order to access similar flow conditions as can be found in real hydraulic turbines. Both the dynamic and dissipation effect of spiral vortex breakdown are investigated. The first part of thesis deals with spiral form of vortex breakdown. The experimentally measured velocity profiles (LDA) and wall static pressures are correlated with numerical simulations carried out using open-source CFD package OpenFOAM 2.2.2. The high speed camera recording of cavitating vortex core is used to obtain image ensemble for further post-processing. The dissipation effect of spiral vortex structure is in detail discussed based on computed flow fields. The second part of thesis is dedicated to the application of POD decomposition to the study of spatio-temporal features of spiral vortex dynamics. Firstly the POD is applied to the both the experimentally obtained image ensemble of cavitating vortex and numerically computed static pressure fields. Secondly the comprehensive analysis of spiral vortex mitigation effect by the axial water jet is analyzed. The collaborative study employing the swirl generator apparatus designed by the researchers from Politehnica University of Timisoara in Romania is performed and changes in spatio-temporal vortex dynamic are studied. In this study the numerical data (in a form of three-dimensional pressure and velocity fields) are obtained using commercial CFD software ANSYS Fluent R14.
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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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Study of hydroenergy potential exploitation of given location
Kollár, Martin ; Hudec, Martin (referee) ; Rudolf, Pavel (advisor)
For the objective of my Bachelor`s thesis I chose an assessment of hydropower potential and a design of machinery in the small hydropower plant construction on the river Váh in Trenčianske Biskupice site. I divided hydropower potential into three parts. First part is the past then present and last is future status. I have subsequently used these information in the design of machinery, including turbine and its associated penstock and draft tube. Part of my thesis also contains appropriate design solution for control gate of intake and outflow, trash rack and trash rack machine. I prepared and presented two possible alternatives together with the drawing documentation which are at the end of my paper compared and evaluated.
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Feasibility study of the pumped storage power station
Kratina, Jakub ; Duchan, David (referee) ; Dráb, Aleš (advisor)
Pumped storage power stations are an integral part of all power systems. At pre-sent, they represent perhaps the only option to accumulate more surplus electricity. It is also built as a proven regulatory element of the power system. The content of this bachelor thesis is a study of feasibility of the pumped storage power stationt (PVE Podlešín) in the Vaňov area. The introduction deals with the issue of pumped srorage power station. Then the design of a technical solution for the power plant construction follows. The main part of the study is the elaboration of drawing documentation and technical reports.
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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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