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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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Shape Optimization of the Machine Components due to Variability of Input Data
Sawadkosin, Paranee ; Jonák, Martin (referee) ; Novotný, Pavel (advisor)
The objective of this Master’s thesis is to find shape optimal design based on min- imizing friction force of thrust bearing by using genetic algorithm(GA) which is one of an optimization toolbox in Matlab. Reducing the friction force of thrust bearing is one way of making shaft to decreasing friction losses. With four parameters of thrust bearing geometry number of segments(m), angle of running surface(), segment inner radius(R0), and segment outer radius(R1) substitute in Reynolds’ equation. In order to know friction force, it is necessary to generate a connecting variable, oil film thickness(h0) from loading capacity(W ) and revolution per minute(rpm). Friction power loss, as well as weight func- tion conclude the final shape optimization of thrust bearing: m = 7, = 0.1, R0 = 15 mm, and R1 = 20 mm.
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Lubricant Gap Shape Optimization of the Hydrodynamic Thrust Bearing
Ochulo, Ikechi ; Vacula, Jiří (referee) ; Novotný, Pavel (advisor)
Cílem této diplomové práce je najít optimální profil mezery mazání pro turbodmychadlo. Cílem je minimalizovat tření, udržovat nosnost a nezvyšovat průtok maziva. Tato multiobjektivní optimalizace se provádí pomocí genetického algoritmu (GA) v MATLABu. Minimalizace třecí síly snižuje ztráty třecího výkonu turbodmychadla. Řešení Reynoldsovy rovnice je počítáno numericky pomocí MATLABu. Je zjištěna minimální tloušťka mazací mezery pro počáteční problém. Funkce spline se používá ke generování obecného profilu mazací mezery. Tento profil je poté optimalizován pomocí GA v MATLABu.
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Lubricant Gap Shape Optimization of the Hydrodynamic Thrust Bearing
Ochulo, Ikechi ; Vacula, Jiří (referee) ; Novotný, Pavel (advisor)
Cílem této diplomové práce je najít optimální profil mezery mazání pro turbodmychadlo. Cílem je minimalizovat tření, udržovat nosnost a nezvyšovat průtok maziva. Tato multiobjektivní optimalizace se provádí pomocí genetického algoritmu (GA) v MATLABu. Minimalizace třecí síly snižuje ztráty třecího výkonu turbodmychadla. Řešení Reynoldsovy rovnice je počítáno numericky pomocí MATLABu. Je zjištěna minimální tloušťka mazací mezery pro počáteční problém. Funkce spline se používá ke generování obecného profilu mazací mezery. Tento profil je poté optimalizován pomocí GA v MATLABu.
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Shape Optimization of the Machine Components due to Variability of Input Data
Sawadkosin, Paranee ; Jonák, Martin (referee) ; Novotný, Pavel (advisor)
The objective of this Master’s thesis is to find shape optimal design based on min- imizing friction force of thrust bearing by using genetic algorithm(GA) which is one of an optimization toolbox in Matlab. Reducing the friction force of thrust bearing is one way of making shaft to decreasing friction losses. With four parameters of thrust bearing geometry number of segments(m), angle of running surface(), segment inner radius(R0), and segment outer radius(R1) substitute in Reynolds’ equation. In order to know friction force, it is necessary to generate a connecting variable, oil film thickness(h0) from loading capacity(W ) and revolution per minute(rpm). Friction power loss, as well as weight func- tion conclude the final shape optimization of thrust bearing: m = 7, = 0.1, R0 = 15 mm, and R1 = 20 mm.
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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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Slide Bearings for High Pressure Pump
Novotný, Marek ; Petr, Jiří (referee) ; Novotný, Pavel (advisor)
The goal of this diploma thesis is to design the journal bearings for high pressure diesel pump which is part of Common rail system from Motorpal Company. This producer is also submitter of this diploma thesis and as a result it is expecting the reduction of cost price and possible transfer to the diesel oil lubrication. Firstly, there is sum up of issues of high pressure pump by Motorpal. The next part of the thesis describes the journal bearings and its construction, tribology of the journal bearings and also the overview of the materials. These materials are currently being used for securing long time usage and do not require service maintenance during lifespan period. In the practical part there is applied the Multy Body System (MBS) approach with rigid bodies and after that there are used analytic relations, which however do not include impact of movement of the journal center during dynamic stress. The thesis concludes with a comparison of results of both calculations and determination of bearing parameters, which according to the calculations ensure an achievement of hydrodynamic lubrication.
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