Effects of temperature dependent air properties on the performances of a thermal actuated slider

Thermal actuated sliders have been widely used in today's hard disk drive industry for its advantages of easier control of flying height (FH) and less risk of contacts with the disk over the conventional slider. In this paper, we used a coupled-field analysis method, which includes an air bearing model, a heat transfer model and a thermal-structural finite element (FE) model to investigate the flying and thermal performances of a thermal actuated slider at various environmental temperatures. We also proposed a generalized mean free path model to incorporate various molecular dynamics models and consider temperature effects of the mean free path. Some temperature dependent air properties, such as the viscosity and the thermal conductivity are also considered in the simulation. It is found that the mean free path is a crucial parameter in determine air bearing and heat transfer across the head-disk interface (HDI). Our simulation results also show that the temperature effects of the viscosity and the thermal conductivity are contrary to that of the mean free path, which limit the variations of air bearing and heat transfer as the environmental temperature increases. However, their temperature effects still need to be considered for an accurate simulation, especially when the disk drives operate in a wide temperature range.