National Repository of Grey Literature 46 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
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.
Pump station design optimization
Kunovský, Lukáš ; Klas, Roman (referee) ; Štigler, Jaroslav (advisor)
This diploma thesis summarizes the necessary knowledge for the design of the pump station. It focuses on the choice of suitable pumps and control valves. It also provides information on mathematical optimization methods. By combining these two disciplines a program was created that selects the most suitable combination of pumps and valves for the assigned requirements. These can vary over time. The goal of optimization is to minimize initial and operating costs. The phenomena considered are: time-varying flow and head height, serial and parallel co-operation of pumps, throttling control, a change of characteristics for variable speed and temperature, suction height control, maximum motor output, loss in connection piping.
Hydraulic part of plunger pump adjustment for higher pressures
Dvořák, Petr ; Klas, Roman (referee) ; Habán, Vladimír (advisor)
First part of the master thesis is about displacement pump. Second part is about power plunger pumps. In the third part are equations for power plunger pumps. In the last part the strength calculation of the proposed hydraulic part of the plunger pump was performed using the finite element method in ANSYS. The screw fatigue life is also calculated here. At the end of this section, ANSYS Fluent flow calculation is performed in the suction valve area.
Pneumatic cylinder
Málek, Miroslav ; Štefan, David (referee) ; Klas, Roman (advisor)
Bachelor thesis contains description and categorization of pneumatic actuators, main part is devoted to linear pneumatic motors, their design and description of individual parts of the motor with respect to its function. Part of this thesis is devoted to buckling stability of the piston rod and brief description of the parts in the pneumatic circuit. Next part of the thesis is deals with description of mathematical model of pneumatic cylinder, which results in simulation of variables describing the operation of the motor. Simulation has been done on double-acting and single-acting pneumatic cylinder with return spring. This mathematical model also includes a friction force model.
Vortex pump as a possible heart replacement
Coufalík, Martin ; Klas, Roman (referee) ; Klas, Roman (referee) ; Fialová, Simona (advisor)
The diploma thesis deals with the issue of artificial hearts and ventricular assist devices. The theoretical part describes the heart and its function. Blood is characterized in terms of rheological behavior and the possible criteria for hemolysis are discussed. The following section describes the most commonly used ventricular assist devices, with emphasis on the use of the regenerative pump, including its components. In the practical part, an experimental analysis of two pumps (COV 43 and COV 23) is performed. Furthermore, non-dimensional characteristics of the pumps are constructed using the laws of similarity. In the computational part, the CFD analysis of the regenerative pump is performed by means of stationary and transient calculation. The results are compared with the experimental findings and based on the results, the impeller of regenerative pump was modified.

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