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Performance and Safety Improvement of Large-Scale Hydrostatic Bearings
Michalec, Michal ; Wodtke, Michal (referee) ; Fillon, Michel (referee) ; Svoboda, Petr (advisor)
Táto dizertačná práca sa zaoberá experimentálnym a numerickým štúdiom veľkorozmerných hydrostatických ložísk. Takéto ložiská sa používajú na presné a plynulé polohovanie veľkých konštrukcií, pretože klzné plochy ložiska sú úplne oddelené externe tlakovaným mazacím filmom. Od jeho prvého oficiálneho predstavenia v roku 1852 prebehol rozsiahly výskum na zlepšenie výkonnosti. Napriek tomu sa výskumníci primárne zameriavali na hydrostatické ložiská malých rozmerov, zatiaľ čo len veľmi malá časť výskumu sa zameriavala na väčšie rozmery tohto typu ložísk. V takýchto prípadoch vznikajú úplne iné výzvy, ktoré sú spojené s vyššou energetickou náročnosťou, výrobou dielov ložísk, dopravou a montážou. Výrobné chyby, nesprávne zarovnanie ložísk alebo neoptimálna konštrukcia môžu zhoršiť výkonnosť ložiska, čo môže viesť až k jeho poruche. Cieľom tejto dizertačnej práce je predstaviť vylepšenia výkonu a bezpečnosti do rozsiahlej metodiky návrhu hydrostatických ložísk. Zlepšenie výkonu ložiska sa vykonáva pomocou numerického modelu oblasti tekutiny, ktorý je overený pomocou experimentálnych a teoretických údajov. Táto štúdia predstavuje úplne nový prístup založený na nezávislej optimalizácii viacerých geometrických parametrov hydrostatickej ložiskovej kapsy. Zlepšenie bezpečnosti sa vykonáva čisto experimentálne. Pozornosť je zameraná na nesúosovosť klzných plôch kapsy a bežca a ich vplyv na výkon ložísk. Okrem toho je skúmaná schopnosť samo-vyrovnávania podložky s použitím poddajnej podstavy. Experimentálna časť bola vykonaná pomocou testovania hydrostatického ložiska pozostávajúceho z dvoch káps s plnou diagnostikou. Ako ukazujú výsledky, navrhovaná metodika optimalizácie geometrických parametrov hydrostatického ložiska môže zlepšiť výkon ložiska až o 20 %. Skúmanie vplyvov nesúosovosti na výkonnosť ložiska ukazuje určitý rozsah, v rámci ktorého môže ložisko stále bezpečne fungovať, zatiaľ čo poddajná podpora môže tento rozsah ešte predĺžiť. Táto štúdia predstavuje originálny výskum rozširujúci poznatky o rozsiahlych hydrostatických ložiskových systémoch smerom k lepšiemu výkonu a vyššej bezpečnosti.
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Influence of inlet hole position in hydrostatic bearing recess using CFD simulation
Androvič, Dominik ; Svoboda, Petr (referee) ; Michalec, Michal (advisor)
This bachelor thesis deals with the influence of inlet hole position in hydrostatic bearing recess in combination with lubricating film tilting using CFD simulation in ANSYS Fluent software. Before the investigation, encapsulation of hydrostatic bearing, CFD simulation and research of hydrostatic bearings was implemented. For investigation of ours the analytical reference model of an axial hydrostatic bearing based on recommended design parameters was created. The main parameters of interest maximal recess pressure and load capacity of bearing were emerged from analytic solution. Subsequently, the maximal recess pressure and load capacity of the bearing were computed using CFD simulation for selected position of the inlet hole and the lubricating film tilt. The results indicate that the load capacity of the bearing is decreasing with the increasing lubricating film tilt. However, in case of alteration of inlet hole position even combined with selected lubricating film tilts no significant changes in maximal recess pressure or load capacity of the bearing with changing in position of inlet hole has been observed. The obtained results might be used to improve the design of hydrostatic bearings.
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Optimization of hydrostatic bearing recess shape
Kopřiva, David ; Omasta, Milan (referee) ; Michalec, Michal (advisor)
This bachelor's thesis deals with the problem of optimizing the recess shape of a hydrostatic bearing. It describes the principle of operation of hydrostatic bearings, their use and previous recess optimizations. A circular recess is considered as the reference geometry. This is firstly investigated by analytical calculation and CFD simulation. The results from the analytical calculation and from the calculation using the CFD simulation are then compared in terms of accuracy of CFD simulation. After verifying the CFD settings, three types of geometry are proposed based on research and previous studies, and with the help of CFD, these geometries are examined with respect to hydrostatic bearing load capacity and recess pressure. All proposed geometry types are then compared with the reference geometry. The results show that the reference geometry has the best results in terms of bearing load capacity and recess pressure. From the point of view of asymmetrical loading and damping, the use of the proposed geometries seems to be more appropriate. This thesis describes a detailed procedure for setting up the CFD and can serve as a basis for further optimization.
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Influence of inlet hole position in hydrostatic bearing recess using CFD simulation
Androvič, Dominik ; Svoboda, Petr (referee) ; Michalec, Michal (advisor)
This bachelor thesis deals with the influence of inlet hole position in hydrostatic bearing recess in combination with lubricating film tilting using CFD simulation in ANSYS Fluent software. Before the investigation, encapsulation of hydrostatic bearing, CFD simulation and research of hydrostatic bearings was implemented. For investigation of ours the analytical reference model of an axial hydrostatic bearing based on recommended design parameters was created. The main parameters of interest maximal recess pressure and load capacity of bearing were emerged from analytic solution. Subsequently, the maximal recess pressure and load capacity of the bearing were computed using CFD simulation for selected position of the inlet hole and the lubricating film tilt. The results indicate that the load capacity of the bearing is decreasing with the increasing lubricating film tilt. However, in case of alteration of inlet hole position even combined with selected lubricating film tilts no significant changes in maximal recess pressure or load capacity of the bearing with changing in position of inlet hole has been observed. The obtained results might be used to improve the design of hydrostatic bearings.
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Optimization of hydrostatic bearing recess shape
Kopřiva, David ; Omasta, Milan (referee) ; Michalec, Michal (advisor)
This bachelor's thesis deals with the problem of optimizing the recess shape of a hydrostatic bearing. It describes the principle of operation of hydrostatic bearings, their use and previous recess optimizations. A circular recess is considered as the reference geometry. This is firstly investigated by analytical calculation and CFD simulation. The results from the analytical calculation and from the calculation using the CFD simulation are then compared in terms of accuracy of CFD simulation. After verifying the CFD settings, three types of geometry are proposed based on research and previous studies, and with the help of CFD, these geometries are examined with respect to hydrostatic bearing load capacity and recess pressure. All proposed geometry types are then compared with the reference geometry. The results show that the reference geometry has the best results in terms of bearing load capacity and recess pressure. From the point of view of asymmetrical loading and damping, the use of the proposed geometries seems to be more appropriate. This thesis describes a detailed procedure for setting up the CFD and can serve as a basis for further optimization.
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