Performance analysis of membrane restrictor hybrid journal gas bearings

The performance of membrane restrictor hybrid journal gas bearings is studied theoretically and simulated numerically. The model of gas flow in membrane restrictor is established and simplified. By employing fluid impedance method, the relation between the flow expression of membrane restrictor and the flow expression of gas bearing orifice restrictor is found. The Newton iteration method is employed to deal with the nonlinear gas Reynolds equation, the finite difference method is used to discretize the equations, the Reynolds equation of the membrane restrictor hybrid gas bearing is solved, the gas flow distribution law of membrane restrictor is obtained and then the bearing load capacity under different rotating speeds and no rotating speeds are acquired. The numerical simulation results indicate that the chamber height and the outlet diameter of the membrane restrictor are the key parameters for the design of the membrane restrictor, the smaller the chamber height and outlet diameter of restrictor are, the greater the load capacity will be; by utilizing the membrane restrictor, the intake gas pressures of orifices decrease, but the intake gas pressure difference among different orifices increases, so the bearing load capacity increases obviously.