PEI Hao, LONG Wei, YANG Shao-hua, GONG Ling
JOURNAL OF VIBRATION AND SHOCK. 2018, 37(5): 71-78.
In order to further improve working accuracy and stability of an air bearing, gas flow state and heat transfer characteristics of its inlet region were analyzed according to the impinging jet theory, the flow field of gas supply hole was divided into four parts including free jet zone, stagnation one, transition one and outlet wall jet one. Based on the two-dimensional planar flow function and the large eddy simulation method, it was determined that micro-vibration of gas film is caused due to three typical cyclonic forms in the inlet region including main cyclone near gas supply hole, sub-cyclone inside gas cavity and additional one at gas film inlet. The evolution mechanism, development law and varying trend of the three cyclones were clarified with the gas molecular motion theory combined with the surface-interface physical method. At the same time, relations among pressure change in gas film, 4 zones’ positions and ranges were studied, location and intensity of pressure fluctuation in gas film were analyzed. At last, vibration amplitude variation and frequency response function of gas film were measured on a test rig to verify the existence and distribution of the three cyclones, and the reasonableness of gas supply hole flow field partition. The influence factors and laws of gas film micro-vibration intensity were also given with the combination of numerical computation and test data.