Head-disk interface modeling with the lattice Boltzmann method

A novel methodology based on the lattice Boltzmann method (LBM) is proposed for the prediction of air-bearing performance. We examined the feasibility of our method by using the second-order slip model as a case study. Extension of our approach using the database obtained from the Boltzmann transport equation (BTE) can be performed to develop an air-bearing design tool for complex geometry. LBM can enhance accuracy and numerical efficiency as well as easy hybridization with lubricants modeling and can be better suitable for an advanced head-disk interface (HDI) design, including the heat-assisted magnetic recording.

I. Introduction

Molecular rarefaction within gaseous lubricating films is critical to the analysis of the head–disk interface (HDI) as the spacing between the slider and the disk becomes extremely small in order to achieve higher areal recording density. The molecular rarefaction effect was incorporated via the Boltzmann transport equation (BTE) by Fukui and Kaneko [1] and Kang, Crone, and Jhon [2] to describe a slip flow using the Knudsen number (Kn) and surface accommodation coefficient and was implemented to accurately simulate slider attitude. Since the trailing edge fly height is only a few times greater than the lubricant film thickness, it is desirable to invent a rarefied gas dynamics model that can incorporate the molecular information of the lubricant layer. The integrated simulation of the HDI includes the air bearing, lubricant film, and nanoscale heat transfer, which are described by several different length and time scales. A realistic HDI design requires coupling of the component technologies, e.g., the air-bearing stability depends critically on the surface morphology of lubricant film underneath the slider. By adopting advanced surface characterization techniques, we can obtain key parameters (e.g., ) that describe the characteristics of lubricant film simulated via molecular dynamics.