Effects of microfabrication defects on the performance of gas bearings with High aspect ratio in microengine

The Molecular Gas-film Lubrication model is combined with the tapered gas film thickness equation so that both the gas rarefaction effects and the taper effects are introduced simultaneously to study the steady-state performance and the stability charts of micro bearings. The results indicate that gas rarefaction effects lessen the load capacity and stiffness coefficients, decrease the damping coefficients at lower bearing numbers but increase them at higher bearing numbers. Meanwhile, compared with the ideal bearing with the same minimum clearance, the taper effects weaken the load capacity, increase the required stable minimum eccentricity and narrow the stable static load region.

► Steady-state performance and the stability charts of micro bearings are studied.
► MGL model is combined with the tapered film thickness equation of micro bearing.
► Gas rarefaction effects lessen the load carrying capacity and the stiffness.
► Taper effects weaken the load capacity and increase the minimum eccentricity.
► Taper effects also narrow the static load region required for stable operation.