National Repository of Grey Literature 50 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
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.
Design of the hydraulic circuit of the ASC 110 vibratory roller drive
Novák, Martin ; Rada, Zdeněk (referee) ; Rada, Zdeněk (referee) ; Klas, Roman (advisor)
This thesis presents a proposal of newly designed concept for travel hydraulic circuit of vibratory single drum roller ASC 110. The maximum machine gradeability was chosen as the main parameter for hydraulic circuit proposal. After selecting the new hydraulic travel concept, suitable hydraulic components have been selected. Length and local losses for two different machine speeds were calculated for sufficient hydraulic circuit design. Hydraulic losses have also been calculated for use in different climatic conditions. A new machine cooling concept has also been proposed. Heating and cooling curves of hydraulic circuit were calculated. For the purpose of comparing gradeability and energy balance of the newly designed travel concept compared to the existing one currently in mass production, both machines were fitted with measuring points. On both machines were measured for example, pressure, flow and temperature in each hydraulic circuit branch and others. From the time dependencies of the above-mentioned parameters it was possible to determine the energy efficiency of the newly designed concept. To assess the maximum gradeability, the slope of the hill was measured. Comparing the two machines, it has been found that the two hydraulic circuit solution has significantly improved traction properties in demanding machine applications, especially when driving uphill and downhill. This concept also affects less fuel consumption and places less demand on the hydraulic oil cooler due to its energy efficiency.
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.
Pulse flow of liquid in flexible tube
Komoráš, Miroslav ; Šedivý, Dominik (referee) ; Klas, Roman (advisor)
This master’s thesis is dealing with analysis of fluid flow pulse in a flexible tube representing e.g. an artery in a human body. In ANSYS program, 3D simulations were performed, and these are so-called interrelated FSI analysis. In Maple software, 1D simulations of fluid flow in the tube were performed for various thin-walled and thick-walled variants. The aim is using these programs to determine the flow rates and pressures in the tube, its wall deformation and stress. Therefore, the theoretical part deals mainly with basic equations of flow dynamics, linear and nonlinear models and rotationally symmetric vessels. In the computational part are described individual procedures in the mentioned programs.
Hydraulic retarder
Ryšková, Marie ; Stareček, Jakub (referee) ; Klas, Roman (advisor)
This thesis is devoted to the design of hydraulic retarder, with emphasis on CFD simulation. The thesis is based on simulation of flow in hydraulic retarder with included transformation of heat. The generation of heat at breaking with hydraulic retarder significantly influences amount of created moment. With use of simulations the anticipated breaking moment emerging on break of a spinning wheel from the design is verified. A group of brake models, in which the hydraulic break belongs to, is introduced in the beginning chapters. This following chapter focuses on design of simulation model that corresponds with the process of breaking. Simple 1D mathematical model for filling the brake with oil using compressed air is introduced.
Testing of proportional hydraulic block characteristics
Vácha, Ondřej ; Klas, Roman (referee) ; Habán, Vladimír (advisor)
Goal of this thesis is to verify functions of hydraulic manifolds from new supplier, measure characteristics of pressure loss relative to flow rate and for proportional blocks also characteristics of flow rate relative to control voltage at constant inlet pressure. Verification will be carried out with proportional manifolds and on/off manifolds with different failure functions.
Optimization of nozzles for firefighter sport
Páral, Filip ; Klas, Roman (referee) ; Fialová, Simona (advisor)
This thesis deals with flow inside of the firesport nozzles. Those are used for a fire attack, one of the firesport disciplines. The research part of this thesis introduces a fire attack, commonly used equipment and hydraulic losses that occur during the flow. This part also consists of an overview of current firefighting and firesport nozzles. It includes requirements for nozzles that are used in the fire attack discipline. Second part of the thesis presents the flow analysis inside firesport nozzles using commercial software for computational fluid dynamics (CFD), ANSYS Fluent. Several nozzle designs are proposed at the end of this thesis, based on conclusions from previous part. These designs satisfy firesport nozzle requirements, previously stated in this thesis.

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