Study On Radial Flying Characteristics Of Disk Head Slider Based On Finite Volume Method

With the continuous increase for magnetic recording density of the hard disk,the clearance between the slider and the disk continue to decrease,which increases the risk of the slider colliding with the disk during the working process of the hard disk.Therefore,the study on the flying characteristics of the slider becomes particularly important.This dissertation combines the Linearied Flow Rate(LFR)model and dynamics equations of the head/disk interface air film lubrication equation(Reynolds Equation)to analyze the influence of radius position on the flying characteristics of the slider.The flying characteristics and its influencing factors during dynamic radial flying are studied.The full text of the study content is as follows:First,due to the complexity of the Reynolds equation itself,an analytical solution cannot be obtained.Therefore,the finite volume method is used to solve the Reynolds equation.The discrete equation of six difference schemes: central difference scheme,upwind difference scheme,mixed difference scheme,QUICK difference scheme,exponential difference scheme,and power-law difference scheme are derived.The calculation time and simulation errors of several difference formats under different grid densities are compared,and further research is conducted.The effects of different difference solution schemes on the pressure simulation results of the air film lubrication equation at the head/disk interface are presented.It is find that the six differential formats can simulate the pressure distribution of the slider.The exponential scheme has high stability under different grid densities,and has higher calculation efficiency and better simulation results than other formats.The scope of application is wider,so the exponential scheme is optimal.Then,based on the air film lubrication equation and dynamic equation of the head/disk interface,the dynamic balance calculation model of the slider is established.Based on this,the comprehensive influence of the initial minimum flying height,pitch angle,roll angle,and disk radius position of the slider on the bearing capacity of the slider are analyzed and compared,and the influence of the disk radial position on the flying characteristics of the slider is analyzed.The study find that the initial values for the three basic flying parameters of the slider and the radius position have significant effect on the flying characteristics of the slider.Among them,the larger the initial value and the disk radius position are,the larger the air membrane bearing capacity becomes;the larger the disk radius is,The larger the fluctuation range for the time-varying curve of the minimum flying height,pitch angle,and roll angle of the slider become.Finally,the dynamic balance calculation model of the slider is used to simulate the dynamic process of the radial flying of the slider during the normal operation of the hard disk,and its flying characteristics are analyzed.The effects of the radial tracking-speed of the slider,the external impact load,and flying over obstacles on the dynamic radial flying characteristics of the slider are further studied.The study conclude:During the dynamic radial flying of the slider,the minimum flying height,pitch angle,and roll angle of the slider fluctuate greatly at the beginning of the flying,and the fluctuation amplitude at the later stage of the flying are small;the greater the radial tracking speed and the helium content are,the smaller the flying height of the slider becomes,the smaller the pitch and roll angle fluctuation are,the smoother the flying becomes;the greater the external interference is,the larger the minimum flying height and pitch angle of the slider becomes,but the smaller the impact on the later flying process.