Numerical Simulations of Accommodation Coefficient Effects at the Head-Disk Interface

Abstract

In this article, we use our proposed heat transfer model, which can be well validated by using the direct simulation Monte Carlo (DSMC) method, to investigate the thermal accommodation coefficient (TAC) effects on the heat conduction in rarefied gas filled head-disk interface (HDI). We also employ some numerical techniques to analyze the slider's thermal and flying performances for arbitrary surface accommodation coefficients. The simulation studies show that as the TAC decreases, the heat transfer at the HDI is reduced, which increases thermal protrusion on the slider and lowers slider's flying height (FH) accordingly. It is also found that tangential momentum accommodation coefficient (TMAC) affects slider's FH more significantly than the TAC. The dependency of TMAC and TAC on the temperature is also discussed based on molecular trapping-desorption theory and a variety of TAC and TMAC values are suggested to improve the accuracy of predicting heat transfer and air bearing at the HDI of hard disk drives.