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Modelling the Oil Lubrication System of Turbocharger
Breckl, Lukáš ; Hliník, Juraj (referee) ; Novotný, Pavel (advisor)
The diploma thesis contains a research part focused on turbocharger construction, engine lubrication system and turbocharger, basic physical properties of lubricating oils and hydrodynamics. The purpose of this thesis is to create analytical and CFD computational model of turbocharger lubrication system. Output pressures and the loss of specific energy are determined.
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Research on the textured journal bearings for engines in automotive
Svoboda, Martin ; Hartl, Martin (referee) ; Omasta, Milan (advisor)
The aim of this thesis is to describe the effect of surface textures of radial journal bearings with polymer coating on friction and damage development using experimental tests. Wear and friction tests of real bearings with different texture geometries and surface materials were performed. It was found that the wear deterioration of the textured aluminum sliding bearing surface and neutral or positive effects on the wear of the textured bearing with polymer coating. The reason for the improvement is the good resistance to high pressures of the polymer coating and the preservation of the texture dimensions throughout the bearing run. The friction test showed an improvement in the frictional properties of the textured surfaces when the amount of lubricant in contact was insufficient. At the same time, a positive effect on tribological properties was demonstrated by reducing the lateral lubricant discharge.
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Computational Analysis Of Dynamic Behaviour Of Journal Bearings
Rak, Vladimír ; Kamenický, Ján (referee) ; Pochylý, František (referee) ; Zapoměl, Jaroslav (referee) ; Malenovský, Eduard (advisor)
This work deals with computational modelling of static and dynamic analyses of journal bearings, with analyses of stability of oil-film motion and analyses of response of the rotor assemblies. At our workplace a new theoretical approach to the modelling of the static and dynamic behaviour of the rigid rotating body in liquid is used. The approach is based on the application of the Navier-Stokes motion eq., equation of continuity and boundary conditions eqs. It is possible to separate the motion of the rigid body and liquid from each other using suitable transformation relations and then it is also possible to separate the stationary and nonstationary motions from each other. A method of control volumes is used for these analyses. The real Bézier body is used for the description of the geometrical configuration and also for the approximation of velocity and pressure functions. Combined the ALE (Arbitrary Lagrange-Euler) method is used, because it´s necessary to generate a new net (to perform new meshing) for a change of the shaft position. The additional effects of the liquid (additional mass, stiffness and damping), which we solved in dynamic analysis, are the function of the single parameter only – the shaft-centre position. There is a large advantage in comparison with the standard approach, which is based on application of the Reynolds liquid eq. Author solving the models of the long and short journal bearing with different geometry, especially the elliptical and cylindrical bearings, with incompressible and compressible journal bearing liquid. If the journal bearing problem is solved, it is possible to include the additional effect of the liquid to the right side of the motion equation of a model rotor assembly. Author analyze a model rotor assemblies with two degrees of freedom, which is supported inside of the two journal bearings on the ends of the rotor (Jeffcott rotor assembly). Author modelling and solveing a response of the model rotor assembly on the forced steady-state vibrations, which was actuating by the unbalanced matter.
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Computational modeling of radial hydrodynamic bearings for water machines
Pokorný, Jan ; Šimek,, Jiří (referee) ; Návrat, Tomáš (advisor)
The aim of this thesis is to calculate the stiffness and damping coefficients for radial hydrodynamic bearings. Cylindrical and lemon hydrodynamic bearings are considered. The solution to this problem mainly depends on the hydrodynamic pressure in the bearing. The numerical solution of the Reynolds equation is used to calculate the pressure. The effect of variable viscosity and density of the lubricant due to temperature changes is considered. The static equilibrium position of the journal centre is also solved. The stiffness and damping coefficients are determined using small amplitude journal motions about the equilibrium position. Three methods for determining these coefficients are presented. The outcome of this thesis is an algorithm for the calculation of stiffness and damping coefficients for cylindrical and lemon bearings. Results for lemon bearings are presented and comparison with the commercial software DynRot BR is made. The benefit of this thesis is the creation of an algorithm for the calculation of journal centre equilibrium position, a new way of incorporating the temperature changes in the viscosity and the density of the lubricant, and the modification of a method for calculating stiffness and damping coefficients based on experimental analogy.
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Measurement of Bearings Power Losses
Musil, Roman ; Raffai, Peter (referee) ; Drápal, Lubomír (advisor)
The intention of this bachelor's thesis is to handle an information about the measurement of losses in radial slide bearings and rolling bearings. In a first section, there is described friction in bearings. The next section is about the comparing machines with static and dynamic conditions. Third section describe methods and means of experimental measurement of losses in bearings under different operating conditions. In fourth section, there is introduced the numerical model for friction losses. In the last section, there is summary of machines and there is depicted possible future development too.
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Design of polymer coating sprayer
Meluzín, Ondřej ; Repka, Martin (referee) ; Šperka, Petr (advisor)
This master’s thesis is aimed on design of polymer coating machine that sprays polymer sliding coatings onto surfaces of crankshaft journal bearings used in car engines. At the beginning of this master’s thesis, basic overview of crankshaft bearings design and materials that are used for sliding coatings is given. Then suitable manufacturing technologies for different materials of coatings are described. After describing basic principles of coating technologies and how crankshaft bearings work, main components used for design of the spraying machine are introduced. Three prototypes of the machine are created in virtual environment to verify ergonomics of control and to fulfill safety requirements. In main part of the thesis, description of all parts and subassemblies, such as frame, spraying circuit, pneumatic regulators and safety features is given. Also functions of all parts of the machine are explained in details. Moreover system for handling and manipulation with coated bearings during all necessary technological operations was created. In addition functionality of the machine was verified and checked by spraying of polymer coating on testing samples and crankshaft bearings.
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Slide Bearings Test Bench
Palán, David ; Knotek, Jiří (referee) ; Maršálek, Ondřej (advisor)
This master’s thesis is focused on measurement of electrical contact resistance. The beginning of the thesis is devoted to the introduction of the electrical contact resistance and electrical parameters of journal bearings. Next part of the thesis deals with engineering design of test rig. In order to verify functional measurement principle, the test rig based on engineering design has been made. In the end of the thesis the measuring devices and the measuring process is described. The measurement results from the test rig are presented.
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Research on the textured journal bearings for engines in automotive
Svoboda, Martin ; Hartl, Martin (referee) ; Omasta, Milan (advisor)
The aim of this thesis is to describe the effect of surface textures of radial journal bearings with polymer coating on friction and damage development using experimental tests. Wear and friction tests of real bearings with different texture geometries and surface materials were performed. It was found that the wear deterioration of the textured aluminum sliding bearing surface and neutral or positive effects on the wear of the textured bearing with polymer coating. The reason for the improvement is the good resistance to high pressures of the polymer coating and the preservation of the texture dimensions throughout the bearing run. The friction test showed an improvement in the frictional properties of the textured surfaces when the amount of lubricant in contact was insufficient. At the same time, a positive effect on tribological properties was demonstrated by reducing the lateral lubricant discharge.
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