Simulation of Static Flying Attitudes with Different Heat Transfer Models for a Flying-Height Control Slider with Thermal Protrusion

摘要

The thermal flying height control (TFC), aka dynamic fly height (DFH), technique has been recently used in the head disk interface of hard disk drives to obtain a lower head-media spacing. The air bearing cooling effect, i.e., the heat conduction between the slider and the air film, has been incorporated in the numerical thermal-mechanical simulation of the slider's static performance. However, the heating effect of the viscous dissipation of the air flow has not been considered yet. In this article, both effects are included in the simulation of a flying slider with its flying height controlled by thermal protrusion, and different models for the air bearing cooling are used to obtain the slider's static flying attitudes. The simulation results directly show that the air bearing cooling is dominant compared with the viscous heating. All of the air bearing cooling models, including a recent one that considers the dependence of the air molecular mean free path on the air temperature, have simulation results close to each other. The largest relative difference in the simulated flying height is less than 9% even when the transducer flying height is lowered to below 2 nm.