A comparison of slider bearing simulations using different models

Recently published air bearing calculations for close spacings or high Knudsen numbers have been contradictory. A. Burgdorfer (1959) introduced a first-order correction to the continuum nonslip boundary condition used in the Reynolds equation. A second-order correction was then suggested by Y. Hsia et al. (1983). Gans (1985) presented developments based on the linearized Boltzmann equation. S. Fukui and R. Kaneko (1986) re-examined Boltzmann's linearized equation and derived a different lubrication equation, the FK model. The present authors have carried out numerical simulations for actual taper-flat slider-bearing designs, using the continuum model, the first- and second-order slip corrections, and the FK model. The calculations show that for Knudsen numbers relevant to this application, the second-order slip model gives a better approximation to the FK equation than the first-order model.<>