Direct Monte Carlo simulation of nanoscale mixed gas bearings

Abstract

The conception of sealed hard drives with helium gas mixture has been recently suggested over the current hard drives for achieving higher reliability and less position error. Therefore, it is important to understand the effects of different helium gas mixtures on the slider bearing characteristics in the head-disk interface. In this article, the helium/air and helium/argon gas mixtures are applied as the working fluids and their effects on the bearing characteristics are studied using the direct simulation Monte Carlo method. Based on direct simulation Monte Carlo simulations, the physical properties of these gas mixtures such as mean free path and dynamic viscosity are achieved and compared with those obtained from theoretical models. It is observed that both results are comparable. Using these gas mixture properties, the bearing pressure distributions are calculated under different fractions of helium with conventional molecular gas lubrication models. The outcomes reveal that the molecular gas lubrication results could have relatively good agreement with those of direct simulation Monte Carlo simulations, especially for pure air, helium, or argon gas cases. For gas mixtures, the bearing pressures predicted by molecular gas lubrication model are slightly larger than those from direct simulation Monte Carlo simulation.

Influence of transport coefficients’ dependence on temperature for gas flow in microbearing

“…They gave a wide spectrum of results for different bearing numbers and different inclination angles. Myo et al 14 applied DSMC for both pure gas and gas mixtures.…”

DSMC simulation of rarefied gas flow over a 2D backward-facing step in the transitional flow regime: Effect of Mach number and wall temperature

“…The DSMC method is a stochastic technique and a successful method for simulations of rarefied gas flows. 39 DSMC is used in aerospace technology, vacuum science and engineering, materials processing and manufacturing, material handling, and nanotechnology sectors. 40 Even though the DSMC method is a time-consuming process, 41 but due to its innate accuracy, it is widely used in the simulation of rarefied gas flows.…”

Probabilistic Sensitivity Analysis of Wear Property for MEMS Gas Bearing

“…The study by Epstein A et al [2,3] comprehensively analyzed the static and dynamic performance of MEMS gas bearing, however did not consider the influence of the rarefaction effect. Previous studies on bearings' rarefaction effect mainly focused on slider bearings [4][5][6] and axial thrust bearings [7][8][9]. Direct simulation of Monte Carlo (DSMC) based on molecular dynamics was the mainstream method for studying slider bearings of a small size.…”