| Summary: | 碩士 === 桃園創新技術學院 === 機械工程系機械與機電工程碩士班 === 104 === The present study is mainly concerned with the lubrication performance of infinitely wide power-law film-shaped rough slider bearings with ferrofluds. Based on the ferrohydrodynamic model of Shliomis and the surface roughness model of Christensen, a generalized ferrofluid-lubricated stochastic Reynolds-type equation is derived for the slider bearing. The film pressure is solved from the Reynolds equation, and applied to obtain the load-carrying capacity. From the velocity distribution, one can obtain the shearing stress in the fluid and friction force on the bearing surface, and then the friction parameter of bearings. Integrating the fluid velocity across the section of the bearing, the required volume flow rate is obtained. In order to compare with the conventional case of a smooth bearing with non-ferrofluids, the performances of rough bearings with ferrofluids in the presence of external magnetic fields are presented and discussed in terms of the variation of the surface roughness parameter, the volume concentration parameter and the magnetic Langevin parameter. According to the results obtained, the effects of surface roughness together with the volume concentration of ferromagnetic particles and the strength of applied magnetic fields have significant influences on the bearing performances. The present results can also provide engineers useful messages in developing slider bearings considering the influences of rough surfaces and ferrofluids with applied magnetic fields.
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