表面粗糙度对硬盘超低飞高气膜静态特性的影响

Effects of Surface Roughness on Static Characteristics of Air Bearing Films in Hard Disk Drives with Ultra-low Flying Heights

硬盘(Hard disk drives,HDDs)是当前信息存储的主要器件,它的尺寸越来越小、容量越来越大,磁头的飞行高度越来越低。基于考虑气体稀薄效应修正Reynolds方程的线性流比(Linearized flow rate,LFR)模型,采用一种无网格法——最小二乘有限差分(Least square finite difference,LSFD)法,求解引入压力流因子和剪切流因子的量纲一雷诺方程,并且研究表面粗糙度对硬盘超低飞高(1～2 nm)气膜静态特性的影响。数值结果表明,表面粗糙度对超低飞高气膜压力分布和承载力的影响较大,而对压力中心的影响较小;飞行高度越低和/或表面粗糙度值越大,对压力分布及承载力的影响越明显;在粗糙度值相同的条件下,仅磁头粗糙且取横向粗糙度时,系统压力分布最高,气膜承载力最大;各种情况下,表面粗糙度对压力中心的变化影响不大,说明磁头飞行比较平稳,系统稳定性较好;另外,基于LFR模型研究表面粗糙度对硬盘气膜静态特性的影响,不仅数值结果精度高,并且具有很高的计算效率。

Hard disk drives（HDDs） are now the most important means of information storage.They continue to be made smaller in size,higher in capacity,and lower in flying height.Generalized non-dimensional Reynolds equation including pressure flow factor and shear flow factor based on a linearized flow rate（LFR） model is solved by using a meshless method called least square finite difference（LSFD） method.Effects of the surface roughness on static characteristics of the air bearing film in HDDs with ultra-low flying heights（1-2 nm） are investigated.Numerical results show that effects of the surface roughness on the pressure distributions and the load carrying capacity are great,while effects of the surface roughness on the pressure center are small.Lower flying height and/or greater value of surface roughness leading higher influence on the pressure distribution and the load carrying capacity.With the same value of surface roughness,the rough head with transverse roughness leads to the maximum pressure distribution and load carrying capacity of the system.The surface roughness does not have much influence on the pressure center,which indicates that the head/slider has good flying stability.Moreover,based on LFR model to investigate the effects of the surface roughness on static characteristics of air bearing films in HDDs,not only good accuracy in numerical results can be obtained but also very high computational efficiency can be achieved.