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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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Elimination of nanoplastics by cavitation and advanced oxidation processes
Kluknavská, Júlia ; Burda, Radim (referee) ; Rudolf, Pavel (advisor)
Táto práca sa zaoberá znečistením životného prostredia mikro a nanoplastami a ich možnou likvidáciou. Práca pozostáva z rešeršnej a experimentálnej časti. V rámci rešerše je opísaná problematika mikro a nanoplatov z hľadiska ich vzniku, disperzie do životného prostredia a živých organizmov. V závere rešeršnej časti sú opísané súčasné možnosti eliminácie mikro a nanoplastov pri čistení odpadových vôd. Súčasné riešenia sú založené prevažne na filtrácii, ktorá však zo svojej podstaty nemôže byť absolútna. Bol vyslovený predpoklad, že pomocou zariadenia CaviPlasma by bolo možné eliminovať mikro a nanoplasty z odpadových vôd. Cieľom práce bolo experimentálne overiť tento predpoklad. Skúšobnou vzorkou bola suspenzia vody a polyamidových častíc, ktorá bola následne vystavená pôsobeniu kavitácie a plazmového výboja. Pri experimente nedošlo ku zničeniu častíc a ani ich k viditeľnému porušeniu. Ukázalo sa však, že plazmový výboj môže iniciovať zhlukovanie sa častíc až do takej miery, že sú pozorovateľné kontinuálne štruktúry mikroplastov. Tento jav by mohol byť potenciálne prospešný pri zachytávaní mikročastíc filtráciou.
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Marine energy utilization
Nehybová, Petra ; Čupr, Pavel (referee) ; Rudolf, Pavel (advisor)
The main objective of the bachelor thesis is processing research study dealing with the use of ocean energy. This is a potential and kinetic energy from a renewable source. There are three options introduced in this thesis, how is possible to transform the energy of the ocean to electric energy, which is usable for customers.
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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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Venturi nozzle shape influence on hydrodynamic cavitation
Mračko, Patrik ; Balko, Marek (referee) ; Rudolf, Pavel (advisor)
Thesis focuses on the influence of various differently shaped diffusers of Venturi nozzle on the cavitation, which occurs during flow of liquid through said nozzle. Several models with different shapes of diffuser's wall were designed. Cavitation in these models was then investigated with numerical calculation. Two physical nozzles were made according to designed models and tested on experimental circuit. As part of the experiment, the cavitation inside the nozzles was measured with flow of liquid corresponding to a large range of cavitation numbers. Results of this experiment were used to determine which model of the nozzle is more effective in creation of a cavitating flow.
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Hydroelastic Response of Hydrofoil Under Cavitation Conditions
Čupr, Pavel ; Koňas, Petr (referee) ; Veselý, Jindřich (referee) ; Rudolf, Pavel (advisor)
Tato disertační práce se zabývá experimentálním a výpočtovým výzkumem přídavných účinků od proudu kapaliny na obtékaný hydraulický profil. Dynamická odezva profilu byla analyzována pro dva typy buzení: buzení odtržením mezní vrstvy a Kármánových vírů a dále buzení pomocí externího budiče připojeného k lopatce. Experimentální měření dynamické odezvy profilu na oba typy buzení bylo provedeno pro lopatku umístěnou v kavitujícím a nekavitujícím proudění. Získané výsledky byly použity pro verifikaci přídavných účinků stanovených s využitím numerického modelování.
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Hybrid turbulence models for strongly swirling flows
Kaplán, Martin ; Štefan, David (referee) ; Rudolf, Pavel (advisor)
The aim of this paper is to investigate using of hybrid turbulence models for strongly swirling flows. The work is focused on the possibility of applying a hybrid SBES model to simulate flow around a hydrofoil. The work further describes the creation of a mesh for the solved domain, the setting of boundary conditions and the setting of the solution for the software FLUENT. The simulation results are compared with experimentally measured values. The work also uses and evaluates data from PIV measurements. The knowledge that the paper brings as part of the results of a research project can be applied in the future in the design of blades of water turbines.
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Hydrokinetic turbines
Zrebný, Radim ; Zemanová, Lucie (referee) ; Rudolf, Pavel (advisor)
Bachelor thesis concerns about problematics of hydrokinetic turbines. First part briefly describes potential areas of utilization. Second chapter includes research of available technical solutions, its operation principles and characteristics, while the main distribution is according to the position of the axis of rotation. Following part describes basic principles of the flow theory and achievable limits of energy conversion. Last part deals with design of hydrokinetic turbine used in paper production. The design has been estimated via Blade Element Theory.
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Modification of the experimental stand for cavitation erosion testing
Spielmann, Šimon ; Hudec, Martin (referee) ; Rudolf, Pavel (advisor)
This bachelor´s thesis is focused on cavitation erosion and modification of experimental stend used for cavitation testing. The thesis is divided into two main parts, theoretical and proposal part. In theoretical part, cavitation effect, occurrence of cavitation, growth and collapse of cavitation bubble is analysed. The theoretical part also focused on negative effects of cavitation impact on material´s surface and types of cavitation erosion testing are discussed. The proposal part is focused on the new proposal of cavitation testing apparatus. The old apparatus and the new proposal of apparatus is described together with description of the cavitation test. The new cavitation apparatus will be used for testing cavitation erosion resistance of material or next research of cavitation phenomenon.
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