Influences of the rarefied effect on ultra-thin film gas lubrication in hard disk driver

This paper describes the influences of rarefaction on thin film gas lubrication characteristics by using theoretical analysis and numerical simulation in magnetic hard disk driver. On the view of film thickness, the area scale less than mean free path only accounts on small parts. However, rarefaction region will increase obviously if considering the aspects of both film thickness and pressure. The numerical results show that, the whole flow regime are at the slip flow regime and the transition flow regime in the case of ultra-thin film gas lubrication. Major performance parameters such as the maximum gas film pressure and load carrying capacity, decrease apparently with considering rarefied gas effect.