Abstract: For the turbulent flow in the air bearing, the Reynold’s equation has no closed-form solution. Computational fluid dynamics (CFD) simulation is time-consuming for large scale orifice arrays. An approximate analytical model for the pressure distribution of the air film in orifice arrays is proposed, which combines equivalent circuit modeling and segmented nonlinear interpolation. Based on the pressure distribution of the air film derived from CFD simulation, a multi-port equivalent circuit model for the steady-state pressure distribution of an orifice unit is established by using linear resistor network, and the resistances in the network are determined. The air film of an orifice unit is subdivided into multiple regions, and a nonlinear segmented interpolation function is fitted by using the PSpice circuit simulation data. The load capacity of an orifice unit is calculated from the interpolation function with an error of 3.70% as compared with the CFD results. The equivalent circuit model for a 44 orifice array is obtained by interconnecting 16 orifice units, and the load capacity of the orifice array can be calculated efficiently. As compared with the CFD simulation, the error of the equivalent circuit model for the 44 orifice array is 8.74% in terms of load capacity while the computational speed is improved by over 3 orders of magnitude.

Key words: Air bearing, Computational fluid dynamics, Equivalent circuit modeling, Orifice array, Segmented nonlinear interpolation