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Check valve
Nehybová, Petra ; Závorka, Dalibor (referee) ; Klas, Roman (advisor)
In this Master thesis are mentioned the most used constructions of non-return valves. Further consist of operation principles, fields of application, properties and diffi-culties connected to non-return valves. Motion plug of check valve in liquid is described based on CFD Software simulation.
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EFFECT OF FLOW PARAMETERS OF WATER AND AIR ATOMIZED SPRAYS ON COOLING INTENSITY OF HOT SURFACES
Boháček, Jan ; Střasák,, Pavel (referee) ; Rudolf, Pavel (referee) ; Horský, Jaroslav (advisor)
Práce komplexně popisuje vodní a vodovzdušné chlazení pomocí metod CFD (Computational Fluid Dynamics) konkrétně s využitím software ANSYS FLUENT. Skládá se ze dvou hlavních částí, z nichž první se zabývá numerickým popisem jediné vodní kapky a druhá popisem směsí kapek představující paprsek válcové a ploché trysky. Je založena převážně na vícefázových modelech proudění a vlastních uživatelsky definovaných funkcí (User Defined Functions, UDF) představujících stěžejní část práce. Uvedené výpočtové modely jsou ve většině případů verifikovány pomocí experimentálních dat nebo jiných numerických modelů. V první části práce jsou teoreticky postupně rozebrány všechny tři použité vícefázové modely proudění. První z nich, Volume Of Fluid model (VOF), byl použit pro modelování jediné kapky (mikromodel). Zatímco zbývající dva, Euler-Euler model a Euler-Lagrange model, byly aplikovány v modelu celého paprsku trysky (makromodel). Mikromodel popisuje dynamiku volného pádu vodní kapky. Pro malé průměry kapek (~100µm) standardní model povrchového napětí (Continuum Surface Force, CSF) způsoboval tzv. parazitní proudy. Z toho důvodu je v práci rozebrána problematika výpočtu normál, křivostí volných povrchů a povrchového napětí jako zdroje objemových sil v pohybových rovnicích. Makromodel se zabývá studiem dynamiky celého paprsku tj. oblastí od ústí trysky po dopad na horký povrch, bere v úvahu kompletní geometrii, tzn. např. podpůrné válečky, bramu, spodní část krystalizátoru apod. V práci je rozebrána 2D simulace dopadu paprsku válcové trysky pomocí VOF modelu Euler-Lagrange modelu na horký povrch. Pro případ s VOF modelem byl navržen model blánového varu. Euler-Euler model a Euler-Lagrange model byly využity pro simulaci paprsku ploché trysky horizontálně ostřikující horkou bramu přímo pod krystalizátorem nad první řadou válečků. Pro Euler-Euler model byl navržen model sekundárního rozpadu paprsku založený na teorii nejstabilnější vlnové délky (Blob jet model). Jelikož diskrétní Lagrangeovy částice tvořily v určitých místech spíše kontinuální fázi, byl navržen a otestován model pro konverzi těchto částic do VOF.
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Solution of the unsteady motion of the body in the liquid flow
Zbavitel, Jan ; Kozák, Jiří (referee) ; Fialová, Simona (advisor)
The thesis deals with CFD solution of flow through mechanical heart valves. The opening part includes a research on the negative impacts of implantation of artificial heart valves and the common approaches used in their modeling. This is followed by a detailed analysis of the dynamic mesh functionality and CFD solution is performed using the open-source library FOAM-extend. Part of the thesis focuses on evaluation of the geometry modifications from the perspective of forming the instabilities of the current and the course of force effects on the valve.
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The dynamic characteristics of check valve
Pavlík, Václav ; Dokoupil, Pavel (referee) ; Habán, Vladimír (advisor)
This master´s thesis provides an overview of all designs of check valves, their usage and typical features. Main purpose of this work is to clear up the phenomenon of check valve slam and the other problems that occur during transients. The check valve slam was measured at the test rig in the hydraulic laboratory. For unsteady flow evaluation after pump shut down was used Gibson method. The dynamic characteristic was possible to create by results from this method. It was achieved without impact of the speed of sound in the fluid. This work also contains 2D transient CFD calculations, which was used for evaluation of the hydrodynamic torque acting on the hinge pin. This approach provides an option to calculate wide range of cases at the expense of not entirely exact geometry. The main contribution of the theoretical study at the beginning of this thesis is its entireness. It might give an important clue when right valve is selecting. For good choice of valve might be helpful to use dynamic characteristics in this thesis presented. Mentioned characteristics were created by new way and its background is in measurements and simplified CFD calculations.
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Optimizing of a hydraulic part of a cooling system of a hot-air slide valve
Melecký, Josef ; Kárník, Jan (referee) ; Štigler, Jaroslav (advisor)
Master´s thesis deals with hydraulic optimisation of a hot blast gate valve. The valve must be cooled down, because of very high temperature that is exposed to. The existing cooling system is oversized and uneffective. This gave opportunity to create a brand new system, that would lower operating expenses. The first part of the thesis is dedicated to comparsion between both systems from the point of the total pressure loss. The second part of the thesis deals with hydraulic optimisation of the new system. Computations are modelled in CFD.
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Integral sediment sampler
Zouhar, Josef ; Štigler, Jaroslav (referee) ; Rudolf, Pavel (advisor)
This thesis deals with analysis of flow inside integral SPM sampler. Flowing is described for one-phase flow and multi-phase flow (water-solid particles) approaches. Results of computational modeling and experimental modeling are compared. Experimental box was constructed and its construction is noticed. Methods of used computational and experimental modeling are described. Optimal computational model is recommended. The theme of this thesis was chosen in co-operation with Czech Geological Survey whitin the frame of project MŽP „SP/1b7/156/07“.
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CFD simulation of the hydrokinetic energy converter using flow-induced vibrations
Vaverka, Jakub ; Bezdíček, Jiří (referee) ; Klas, Roman (advisor)
Flow-induced vibrations on bodies of different shapes are investigated by CFD simulations. The influence of the mass of the body, the spring stiffness and the value of the added damping on the dynamic behaviour of the system is evaluated. A combination of the 6DOF function and a dynamic computational mesh is used to move the body around the y-axis solely by fluid flow. The output is an evaluation of the forces acting on the body, the trajectory of the body and the possible power that the body could generate by its motion.
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Check valve
Nehybová, Petra ; Závorka, Dalibor (referee) ; Klas, Roman (advisor)
In this Master thesis are mentioned the most used constructions of non-return valves. Further consist of operation principles, fields of application, properties and diffi-culties connected to non-return valves. Motion plug of check valve in liquid is described based on CFD Software simulation.
|
|
|
Solution of the unsteady motion of the body in the liquid flow
Zbavitel, Jan ; Kozák, Jiří (referee) ; Fialová, Simona (advisor)
The thesis deals with CFD solution of flow through mechanical heart valves. The opening part includes a research on the negative impacts of implantation of artificial heart valves and the common approaches used in their modeling. This is followed by a detailed analysis of the dynamic mesh functionality and CFD solution is performed using the open-source library FOAM-extend. Part of the thesis focuses on evaluation of the geometry modifications from the perspective of forming the instabilities of the current and the course of force effects on the valve.
|
|
|
The dynamic characteristics of check valve
Pavlík, Václav ; Dokoupil, Pavel (referee) ; Habán, Vladimír (advisor)
This master´s thesis provides an overview of all designs of check valves, their usage and typical features. Main purpose of this work is to clear up the phenomenon of check valve slam and the other problems that occur during transients. The check valve slam was measured at the test rig in the hydraulic laboratory. For unsteady flow evaluation after pump shut down was used Gibson method. The dynamic characteristic was possible to create by results from this method. It was achieved without impact of the speed of sound in the fluid. This work also contains 2D transient CFD calculations, which was used for evaluation of the hydrodynamic torque acting on the hinge pin. This approach provides an option to calculate wide range of cases at the expense of not entirely exact geometry. The main contribution of the theoretical study at the beginning of this thesis is its entireness. It might give an important clue when right valve is selecting. For good choice of valve might be helpful to use dynamic characteristics in this thesis presented. Mentioned characteristics were created by new way and its background is in measurements and simplified CFD calculations.
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