A two–dimensional model for the interaction between lubricant droplet on the slider surface and air flow within the head/disk interface of disk drives

Abstract

We numerically study the interaction phenomenon between a lubricant droplet located on the slider’s air bearing surface and the air flow within the head/disk interface of disk drives. A very strong interaction between the lubricant droplet motion and air flow is discovered for ultra-low-flying slider design. The lubricant droplet is driven to migrate towards the slider’s trailing edge by a net effect of air shearing, air bearing pressure gradient, and disjoining pressure gradient. The droplet simultaneously undergoes significant shape deformation. The moving and deforming droplet in turn modifies the effective air bearing surface profile and induces a corresponding air flow adjustment. For a simplified two-dimensional (2D) slider with a fixed flying attitude, our results show that the moving and deforming lubricant droplet induces significant air bearing force and pitch moment change. The interaction becomes stronger when the size of the droplet and the disk’s linear velocity are increased, and when the flying height and pitch angle of the slider are reduced. Our results indicate that a lubricant droplet contamination entering the air bearing surface may impose a non-negligible disturbance on the slider’s flying dynamics.