METHOD FOR INCREASING LOAD CAPACITY ON POROUS AEROSTATIC BEARING WITH TWO-PHASED FLUID

摘要

A method for increasing load capacity on a porous aerostatic bearing through use of a two-phase fluid that is less viscous than lubrication oils and the bearing gap is of the size of air bearings. The porous material throttles vapor and liquid. As liquid goes through the porous media, the pressure drop from the porous media resistance causes it to vaporize. The increased volume flow in the bearing gap reduces the vapor flow rate through porous media, resulting in higher pressure in gap. As the vapor-liquid mixture escapes from bearing gap, another vaporization occurs at the end of bearings which retards escaping, and further increases pressure in the gap. The liquid portion of the two-phase fluid in the bearing gap increases the load capacity and stiffness, similar to hydrostatic bearings fed with liquid. The vaporization absorbs heat generated by bearing friction to allow higher relative speed between bearing surfaces.