Derivation of the modified molecular gas lubrication equation - a porous media model

A porous media model has been developed which can be applied to ultra-thin gas film lubrication problems encountered in the analysis of a magnetic head slider flying over a magnetic disk coated with giant molecule liquid. In this model, the textured surface coated with giant molecule lubricant is replaced with a permeable material. The appropriate slip-flow boundary conditions, i.e. the high-order slip-flow model, and the proper porous flow model, i.e. the Brinkman-extended Darcy model, are utilized in the gas film and porous film, respectively. The modified molecular gas lubrication (modified MGL) equation is then derived by consideration of the permeability of the running surface. Finally, the effects of porous film thickness (Δ), permeability (K) and inverse Knudsen number (D) on the performance of the magnetic head slider are discussed.