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Excessive pressure energy recovery in liquid transport systems
Luky, Samuel ; Bezdíček, Jiří (referee) ; Rudolf, Pavel (advisor)
Táto práca sa zaoberá využitím prebytočnej tlakovej enrgie vo vodovodných potrubiach a spôsobmi ako ňou produkovať elektrinu. V prvej časti sú zhrnuté všetky použitelné riešenia, to sú čerpadlová turbína, AXENT a STRAFLO turbína a turbína s protibežnými obežnými kolesami. Druhá časť je venovaná návrhu axiálnej turbíny pre špecifickú samosprávu mesta Ferlach v Rakúsku. Návrh je následne otestovaný pomocou zjednodušeného CFD výpočtu pomocou programu ANSYS fluent. Výsledky sú zhodnotené a ďalšie kroky na zlepšenie sú navrhnuté.
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Design of nozzle for ozone admission
Krajcar, Ivo ; Hudec, Martin (referee) ; Rudolf, Pavel (advisor)
The thesis consists of three main parts. The first part contains a research focused on cavitation and fractal geometry. Furthermore it researches disinfection, mainly disinfection using UV radiation and ozone. It is concluded by mentioning advanced oxidising processes used for dangerous pollutant elimination and pointing out of positives and negatives of the individual technologies. The main goal of the fractal geometry research was to briefly explain what a fractal is and how to create different types and degrees of fractals. The second part of the thesis contains a simplified description of the design of a fractal orifice with air suction. This orifice is compared to a simple orifice with a circular opening in the last part of the thesis. Both orifices have the same cross section flow area. This part also describes a simple UV reactor design process. The third part of the thesis describes the experimental measurements of both of the orifices. The data gained from the measurements show that the fractal orifice has a better mixing influence than the circular one and also that the fractal orifice has a wider operational range than the circular one.
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Cavitation behind porous orifice
Livora, Tomáš ; Zeman, Radek (referee) ; Rudolf, Pavel (advisor)
This bachelor's thesis deals with the research and experimental verification of cavitation in a porous medium. The research part addresses the inception of cavitation on an orifice plate with one or more holes and the inception of cavitation on a porous structure. In this section, several geometric parameters are established, based on which porous materials can be compared. Their influence on the inception of cavitation is also outlined. In the experimental part, several orifice plates with a porous structure are designed and manufactured based on these parameters, and their properties are subsequently measured in a hydraulic circuit. The evaluated data determine the impact of individual parameters on the inception and course of cavitation.
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Vortex induced vibrations
Szarka, Beáta ; Pluskal, Tomáš (referee) ; Rudolf, Pavel (advisor)
Tato bakalářská práce se zabývá kmitáním vyvolaném vírami na různých průřezech. Teoretická část poskytuje přehled současných trendů výroby energie a představuje typ hydrokinetického sběrače energie VIVACE konvertor. Hlavním principem systému je odtrhávání víru a vznik Kármánové vírové stezky podél tělesa ponořeného do proudící tekutiny. Praktická část se zabývá vyhodnocením různých profilů podle sil působící na těleso, frekvencí a Strouhalového čísla pomocí 2D CFD simulací. Výstupem je výběr ideálního tvaru průřezu válce pro konvertor VIVACE.
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Design study of energy harvestor based on vortex induced vibrations
Háze, Matyáš ; Habán, Vladimír (referee) ; Rudolf, Pavel (advisor)
The formation of vortices and periodically acting forces during the flow around bodies has been a long-standing issue addressed by engineers. Most of the focus has been on minimizing and suppressing these phenomena, which adversely affect engineering structures. However, it appears that it might be possible to amplify this phenomenon and purposefully use it for energy production. Several research projects have already been conducted on this issue, and another is currently underway in collaboration with other European universities at the Viktor Kaplan Department of Fluid Engineering. This bachelor's thesis aims to conduct a review of the ongoing projects and propose a new solution, which will be tested in the OFI laboratories and will be part of the ongoing measurements.
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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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Energy recuperation in water delivery system
Pavlík, Šimon ; Rudolf, Pavel (referee) ; Himr, Daniel (advisor)
The thesis deals with the use of energy potential in water supply networks and is divided into three main parts. The first part describes the characteristic elements of the water supply network and analyses the energy potential of the Nové Bránice water supply system, which was identified in the location of the pressure reducing valve. The second chapter is devoted to designing algorithm according to which a system of energy recovery - a pump in turbine mode is designed. The statistical analysis is counted as well. In this chapter, the theory of pump in turbine mode operation and the prediction theory of turbine characteristic estimation are presented. The final part of the thesis is devoted to creating a water network model in Epanet 2.2. In one day simulations the current state of the system with a pressure reducing valve is compared with the system including the proposed pump in turbine mode.
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Utilization of hydrodynamic cavitation for water treatment
Balko, Marek ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
This bachelor thesis deals with the observation of features of cavitation with emphasis on the hydrodynamical cavitation and its use for eliminating unwanted and badly degradable compounds from water. Thanks to high temperature and pressures that are present at a colapse of cavitation bubbles the water decomposes into highly reactive hydroxile radicals which are able to decompose even. This effect can furthermore be strenghtened by the use of advanced oxidation processes – AOP. The experimental part of thesis is dedicated to examining a ability of hydrodynamical cavitation degrade particular chemical substance from water, namely estrogen.
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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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Experimental testing of minimixer for waste water treatment
Luňák, Pavel ; Štefan, David (referee) ; Rudolf, Pavel (advisor)
This thesis deals with various ways of mixing mainly liquids. The theoretical part is devoted to the distribution of mixers, including a description of their characteristics, advantages, disadvantages and applications. The experimental part is devoted to the measurement of minimixers, which were developed and manufactured V. Kaplan Department of Fluid Engineering. This section contains a proposal of measuring ciruit to determine the hydraulic characteristics of minimixers and the degree of mixing. The measurement results and their evaluation is summarized in the conclusion.
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