Dynamic Lubrication of Micro Gas Bearings at an Ultra High Speed

Micro bearings of Power MEMS are usually designed to work at an ultra high speed more than 10~(6) r/min in order to improve their specific energy. So the dynamic lubrication of micro gas bearings at an ultra speed is researched. First the micro structural characteristics of micro gas-lubricated bearings are investigated, and a method to caculate the load-carrying performance of micro dynamic gas-lubricated bearings is put forword. Then the designs of two typical micro dynamic gas-lubricated bearings that are used in micro gas turbines are vertified. Moreover, the parameters affecting the load-carrying performance of micro dynamic gas-lubricated bearings are analysed.     

Key Techniques for Design and Manufacture of Micro Gas Turbine Engine

The characteristics of flow and combustion in micro gas turbine engine with the low Reynolds number and the high Mach number, the high Couette number and the low Biot number, as well as the ultra high duty ratio of combustion in very small space are analyzed, which are remarkably distinguished from those on macro scale. At the meantime, the limitation of traditional dynamic lubrication theory at ultra high speed on micro scale is presented, and the possibility of making the gas bearing to be able to work at ultra high speed by utilizing boundary slip is investigated. Due to the applied prospect of silicon carbide in the field of MEMS especially under high temperature and high strength conditions, the technical process of combining silicon etching with reactive sintering and grinding machining of silicon carbide is put forward so that the miniature machining of silicon carbide for micro gas turbine engine becomes possible.