Formation Mechanism of Micro-vibration in Aerostatic Bearing Used in Miniature Aircraft Engine

摘要

In order to further improve the working accuracy and stability of air bearing, the gas flow state and heat transfer characteristics of the inlet region of the air bearing are analyzed according to the impinging jet theory, and the flow field of the gas inlet region is divided into Four parts, namely: free jet zone, stagnation zone, transition zone, outlet wall jet area. Based on the two-dimensional planar flow function and the large eddy simulation method, it is determined that the micro-vibration of gas film is originated from three kinds of typical cyclonic forms in the inlet region, namely, the main cyclone near the gas supply hole, the sub-Additional cyclone at the membrane inlet. The evolution mechanism, development law and trend of the three cyclones were clarified by the gas molecular motion theory combined with the surface-interface physical method. At the same time, the relationship between the pressure change and the position and the range And the location and intensity of the pressure fluctuation in the film were analyzed. At last, the vibration amplitude and frequency response function of the air bearing gas film were tested to testify the existence and distribution of the three types of cyclones, which proved the reasonableness of the design of the flow field in the inlet region. The influence factors and laws of micro-vibration intensity of gas film are also given by the combination of calculation and experimental data.