Effects of second-order slip-flow on the steady performance of micro gas bearing

The effects of slip flow on the steady mechanical performances of the micro gas bearing are discussed. Considering the dimensional characters of the micro bearing and judging from the flow's Knudsen number, the flow in the bearing is in the slip regime instead of the continuous regime. The modified Reynold's equations of first-order slip-flow and second-order slip-flow for the micro gas bearing are obtained. Solving the Reynold's equations for the continuous regime and the two slip regimes with the finite difference method (FDM), the gas pressure distributions, the non-dimensional load capacities and attitude angles are obtained. The comparisons of the load capacities and attitude angles between the three regimes are made, and it is shown that the mechanical performance with the slip regime distinctly differs with that of the continuous regime. An analysis illustrates that the slip flow regime has great effects on the steady mechanical performances of the micro bearing. The second-order slip-flow model can produce a good result for high eccentricity ratio operation.