Mathematical modeling of lubrication for the head-disk interface using incompressible fluids

Abstract

In order to keep pace with the demand for higher storage densities in magnetic recording disk drives, new technology must be developed to reduce the tribological problems associated with ultralow flying. Non-Newtonian liquid bearings may become a feasible alternative to slider miniaturization due to the decrease in slider-disk contacts. Issues pertaining to modeling the head-disk interface are presented, and non-Newtonian effects are described. Generalized Newtonian fluid models describe the dependence of the apparent viscosity on the shear rate for bulk fluids, but the extremely high shear rate and the confined geometry at ultralow flying heights complicate conventional non-Newtonian rheological models. Equations are developed for generalized Newtonian fluids which can determine the flying characteristics of recording sliders in viscoelastic drives. Order-of-magnitude analyses are performed in order to determine the effect of drive parameters and fluid properties on the load bearing capacity of the slider and power consumption due to frictional forces. The results obtained are new and may become important in providing design criteria for VISqUS drives or to related design engineers.