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Application of cavitation in industrial processes
Hamar, Oliver ; Tancjurová, Jana (referee) ; Rudolf, Pavel (advisor)
The bachelor thesis deals with the research of the application potential of cavitation technologies in various industries. Thanks to its properties, cavitation seems to be a promising tool for streamlining a large number of industrial processes in several aspects. The first part deals with the theoretical description of the cavitation phenomenon, its negatives and methods of their detection. The second part focuses on the analysis of possible usage areas of cavitation technologies and the ways of generating the cavitation, focusing on current research and findings in the area of hydrodynamic cavitation application.
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Cavitation erosion mechanisms
Kotoulová, Helena ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
Předložená bakalářská práce se zabývá mechanismy kavitační eroze a je rozdělena na dvě hlavní části. Teoretická část popisuje princip kavitace, způsob jejího vzniku a především kolaps kavitačních bublin, který negativně ovlivňuje povrch obtékaného tělesa (např. na hydraulických strojích). Z tohoto důvodu je nutné podrobně studovat účinky kavitační eroze. Experimentální část je věnována testování kavitační eroze na kovových a plastových vzorcích vytisknutých na 3D tiskárně. Plastové vzorky byly srovnávány navzájem mezi sebou, kovové vzorky z 3D tiskárny se vzorky odlitými. O vlivu kavitační eroze na součásti vytisknuté na 3D tiskárně je stále ještě málo informací, i když se jedná o velmi progresivní a stále častěji používaný typ výroby.
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Flow visualization
Vavrla, Zdenek ; Šperka, Oldřich (referee) ; Rudolf, Pavel (advisor)
This bachelor´s thesis deals with fluid flow visualization methods in the air and water. First brief characteristic of the basic concepts of fluid flow is described, such as streamline, laminar and turbulent flow. The described visualization methods are divided into certain types and are used for fluid or gas. These methods provide a qualitative view of the flow and create the overview of the characteristics of gas or liquid flow. Some of these methods are simple and some are more complex. Finally, a simple experiment of liquids flow visualization is described by very powerful laser pointer.
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Influence of the Francis turbine stay vane trailing edge shape on generation of Karman vortex street
Novotný, Vojtěch ; Skoták, Aleš (referee) ; Rudolf, Pavel (advisor)
In the flow past bluff bodies for a certain range of velocity a periodical vortex shedding emerges which is known as von Kármán vortex street. This phenomenon causes the periodical alteration of pressure field which affects the body. Should the vortex shedding frequency be similar to the body natural frequency, the amplitude of vibration significantly increases which can lead to fatigue cracking. In the case of water turbines, this phenomenon often affects the stay vanes. Both the vortex shedding frequency and the lift force amplitude can be influenced by the modification of the trailing edge geometry. The aim of this thesis is to use CFD computation in order to find the optimal geometry of the stay vane trailing edge for the specific Francis turbine unit.
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Dialysis pump
Švagera, Roman ; Rudolf, Pavel (referee) ; Fialová, Simona (advisor)
Dialysis is still very important treatment process today which needs to be constantly improved. This thesis focuses on the development of a pump for dialysis units, specifically on the pressure pulsations reduction in the rotary peristaltic pump. Using experiments, the problem of peristaltic pumps is explained. With the computational modelling there are proposed design modifications leading to the pressure pulsations reduction.
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Shape optimization of hydraulic turbine diffuser
Hliník, Juraj ; Popela, Pavel (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with mathematical optimization focusing on the shape optimization in fluid mechanics with help of a CFD software. More specifically, it comprises the shape optimization of a swirl turbine draft tube with a specified rotational symmetry and the whole process is realised with Nelder-Mead and BFGS algorithms. The main object was to maximalize the pressure coeficient, with help of the algorithms which were implemented in Matlab software.
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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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Flow around winglet
Grešáková, Kristýna ; Rudolf, Pavel (referee) ; Sluše, Jan (advisor)
The first part of this bachelor´s thesis deals with the use of winglets and fluid flow around them. The second part provides a view of model experiments, anemometry and visualization of flow. The final section focuses on real experiment in aerodynamic tunnel.
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Cavitation testing using cavitating jet
Rovder, Juraj ; Dobšáková, Lenka (referee) ; Rudolf, Pavel (advisor)
This thesis deals with the issue of cavitation and its effects. In this context, it describes the mechanism of origin and implosion of cavities and cavitation regimes. It lists various types of hydrodynamic cavitation. It presents the Rayleight-Plesset equation and describes micro jet. It also highlights cavitation erosion and the effects of cavitation on some types of materials. It deals with three types of cavitation resistance testing, namely cavitation tunnels, a vibrating cavitation system, supported by the ASTM G32 standard, and last but not least, cavitation nozzles, which follow the ASTM G134-17 standard. In correlation with cavitation nozzles, it frames its four basic parameters, which are stand of distance, the cavitation number, the speed of sound and the geometry of the nozzle. At the end of the theoretical part it characterizes the construction of test bench. The practical part is focused on performing the experiment. It first presents the procedure for carrying out the experiment and then evaluates this experiment. Part of the evaluation is the visual observation of selected samples of AlCu4Mg1Mn1 material and the monitoring of cavitation erosion on specific samples. First, these data are processed in the form of graphs and tables. It uses a microscope as a tool for detailed observation of samples. The conclusion of the practical part is devoted to the evaluation of the experiment.
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