| New disk technologies are being developed because the demand for disks is increasing.Heat assisted magnetic recording(HAMR)is considered to be one of the most promising technologies to satisfy consumers' demand.The HAMR technology puts more stringent requirements on the lubrication between head disks.And the characteristics of lubricant have a significant effect on the stable work of the disk.In this paper,the interaction of gas film,lubricant film and heat source in disk is studied by using a new simulation model which is closer to the actual working situation.And some suggestions are given to select the working parameters of the hard disk drivers.In this paper,the rarefied effect of gas was taken into account to derive the modified Reynolds equation.Based on the continuity theory of fluid and the NavierStokes equations,the flow equation of lubricant film was established.And the expression of the flow equation in cylindrical coordinate system was also deduced,which laid the theoretical foundation for the disk rotation model.Besides,a heat source resulting from a near-field laser was introduced to obtain the lubricant film deleption equation in the disk rotation model.The air pressure and the lubricant film flow of the two kinds of sliders was solved by using the rotation model and the translation model of disk respectively.And the correctness and progress of the rotation model has been proved.The effects of the head attitude and the head position on the air pressure and the lubricant film thickness were studied by using the new simulation model.The importance of a reasonable air bearing surface was also demonstrated.In this paper,the force distribution on the air bearing surface was evaluated by quantitative method,which provided a theoretical basis for predicting the flow of lubricant film.In addition,some reasonable suggestions about selecting disk operating parameters were also presented in this paper.The effect of the heat source on evaporation of lubricant film was studied.The superposition effect of the near-field laser and the air pressure on the lubricant film was analyzed.By contrast,the near-field laser and the air pressure affecting the lubricant film respectively was also analyzed.The main factor causing the change of lubricant film in HAMR disk under specific working conditions was discussed.The effects of the laser power,the laser spot radius,the lubricant molecular weight and the initial film thickness of lubricant film on the film thickness change of lubricant film were investigated,and the causes of these phenomena were also studied.Some suggestions for guiding the design of HAMR technology disk were put forward.A new gas film thickness function was established according to the surface morphology of the lubricant film after deformation,which was used to study the influence of the lubricant change on the force that sliders suffering.The effect of head attitude and flying height on the interaction between film thickness change and air pressure was investigated.The situation when the change of lubricant thickness and air pressure is considered as a strong coupling was explained.In addition,this paper presented a method for approximately describing the surface of lubricant film after change and demonstrated it. |
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