National Repository of Grey Literature 56 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
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.
Non-newtonian liquids flow
Mašán, Roman ; Klas, Roman (referee) ; Himr, Daniel (advisor)
The bachelor's thesis explores the topic of Non-Newtonian fluids, which behave unusually compared to Newtonian fluids. It characterizes their rheology, clarifies the reasons and mechanisms responsible for their non-standard properties. The thesis also includes a mathematical description of modeling these fluids, which is subsequently applied to elucidate the nature of flow and phenomena occurring in laminar and turbulent regimes.
Multiphase flow simulation of mixing phenomena in a chemical reactor
Novosád Kluknavská, Júlia ; Kožušník, Martin (referee) ; Klas, Roman (advisor)
Predkladaná diplomová práca sa zaoberá problematikou priemyselného miešania a jeho CFD simuláciou. Práca kvalitatívne pokrýva teoretické pozadie miešacích procesov, t.j. dáva všeobecný prehľad o priemyselných miešačoch a ich využití, predstavuje konkrétne typy miešacích vrtulí a poskytuje základné odporúčania pre zostavenie miešacej aparatúry. Hlavná časť práce je zameraná na praktické využitie CFD simulácii pre priemyselnú aplikáciu. Na to, aby bol CFD model fyzikálne správny je potrebná jeho validácia experimentom. Práve preto bol navrhnutý a uskutočnený experiment, v rámci ktorého bol pozorovaný tvar a hĺbka vodnej hladiny pri vírivom prúdení a zaznamenávaná doba rozpúšťania tuhej kryštalickej látky. To isté bolo nasimulované pomocou CFD. Konečné porovnanie CFD simulácie a experimentu preukázalo zhodu tvaru hladiny a jej hĺbky. Model pre simuláciu rozpúšťania je v súlade s reálnym fyzikálnym procesom ale je nutné ho vylepšiť. V práci je však popísaný vhodný spôsob, ako postupovať k získaniu CFD modelu fyzikálne správne popisujúceho rozpúšťanie kryštalických látok.
CFD simulation and analysis of hydrocyclone
Moravanský, Richard ; Burda, Radim (referee) ; Klas, Roman (advisor)
The main goal of the thesis is the design, analysis, CFD simulation and optimization of a hydrocyclone in order to increase the separation efficiency. The reason for this investigation is the lack of information about the design aspects of the hydrocyclone and their effect on the separation efficiency. An important part of the thesis is the teoretical knowledge, which mainly includes a description of the basic parts and a description of the flow. Furthermore, there are discussed the operation itself and the separation theory of the hydrocyclone, with the aim of deriving the basic assumptions and empirical equations. An important criterion for evaluating efficiency is the dependence of this parameter on the size of the particles dp and related phenomena leading to an increase the pressure loss in the device. The CFD simulation is performed by the ANSYS Fluent program, where the discrete phase model DPM was set. As part of the flow analysis, basic contours and a comparison criterion were defined, which describes the negative phenomena associated with the separation efficiency. During the subsequent evaluation, it was concluded that the most important parameter that fundamentally affects the efficiency is the internal dimension of the vortex finder, while the optimization of the geometry of the inlet part had only a minimal effect on the separation efficiency.
Unsteady CFD simulation of flow under a downward moving gate
Málek, Miroslav ; Štefan, David (referee) ; Klas, Roman (advisor)
Emergency gates are important safety feature of hydropower plants. They are used to close the flow in order to protect power plant equipment in case of emergency. In this diploma the-sis are realized CDF simulations of emergency closure of wheel-mounted gate on two-dimensional model of the Slapy hydropower plant. Simulations were performed for the case of constant lowering gate speed and for the case of gravitational closure. Dynamic mesh was used to enable the gate motion. The 6DOF method was used for the case of gravitational clo-sure and user defined function was defined to control movement of the gate. User defined function include gravitational force, hydrodynamic forces and friction force. Simulations were used to verify forces acting on gate and volume flow through gate during closing process. In case of gravitational closure the speed and orientation of closing process and closing process time were determined.
Flow of Newtonian liquid through a flexible tube
Slonek, Matouš ; Illík, Jakub (referee) ; Klas, Roman (advisor)
This bachelor's thesis focuses on the flow of newtonian liquid through a flexible tube. The theoretical part consists of a review of various fields that flexible tube occurs in. In the next chapter were defined equations describing the flow of a liquid through a deformable tube and lastly, constitutive material models were stated. In the practical part, a one-dimensional FSI simulation of the flow of a liquid through a flexible tube was realized.
Analysis of pulse wave propagation in aorta
Tichoň, Dušan ; Klas, Roman (referee) ; Burša, Jiří (advisor)
The aim of this diploma thesis is to assess the applicability of pulse wave propagation monitoring in the cardiovascular system in the field of prediction and early diagnosis of abdominal aortic aneurysm (AAA). The very first part is focused on description of heart and blood vessels with its pathological changes in presence of aneurysm. For this reason, current methods of monitoring and surgical treating of AAA were mentioned. Due to their difficult clinical use widely in the population, new methods based on pulse wave monitoring were presented. Using an analytical approach we estimated the difference in the arrival of the pulse wave at measurable locations between healthy and pathological aorta in the order of miliseconds. By experimental monitoring using photoplethysmographic sensors, we observed significant changes of pulse wave velocity with respect to the mechanical properties of the artery wall (mainly associated with age), which we tried to implement by hyperelastic material models used in computational simulations of pulse wave proagation on simplified geometries by fluid structure interaction method. These analyzes should verify applicability of FSI simulations in further development of diagnostic methods of AAA.
Hydraulic braking systems
Požár, Vladimír ; Závorka, Dalibor (referee) ; Klas, Roman (advisor)
This bachelor’s thesis is focused on processing information about the hydraulic braking system. It describes the basic parts and diferrent types of brakes contained in the hydraulic braking system. It explains the principle of brakes. Most attention is paid to the hydraulic retarder part from the point of view of principle and basic equations for calculating the filling ratio. The final chapter includes a comparison of brakes and use of a hydraulic braking systém.
Reversible swirl turbine
Palička, Miroslav ; Klas, Roman (referee) ; Haluza, Miloslav (advisor)
This diploma thesis describes hydraulic design of Swirl turbine, dedicated to be used for tidal powerplant and study possibilities of the turbine to work in turbine, reverse turbine, pump and reverse pump regime. From individual regimes, graphical characteristics of created hydraulic design were created and compared, using CFD simulations.
Fluid flow analysis in the open cylindrical container with the free surface vortex
Illík, Jakub ; Klas, Roman (referee) ; Štigler, Jaroslav (advisor)
This master's thesis analyses fluid flow in an open cylindrical tank with vortex using numerical simulation. The theoretical part introduces a set of equations governing fluid flow and relations used to describe vortex motion. A general overview of terms used in computational fluid dynamics is presented. The experimental section consists of three parts. The vortex modelling is performed using ANSYS Fluent software. Data are consequently analysed within ANSYS CFD-Post software tool. Special focus is put on the vortex shape that is fitted with a curve corresponding to a probability density function of the Cauchy distribution. Results are then plotted in MATLAB software.

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