Simplified Second Order Reynolds Equation for Simulating Ultra-Thin Gas Film Lubrication in the Head/Disk Interface

To increase the recording density of magnetic disk drives, the spacing between the flying slider and the rotating disk should be as small as possible. If the spacing between the flying head and the rotating disk approximates the molecular mean-free path, rarefaction effects must be taken into account. Starting from a Poiseuille flow rate database, a simplified precise second order (PSO) model is proposed to simulate ultra-thin gas film lubrication. The new model is evaluated using the finite volume method. The numerical results are compared with other models, including the widely used FK (Fukui and Kaneko) model. The new PSO model has three key advantages compared to other models. First, compared with the 1^st-order model, the 2^nd-order model and the 1.5^th-order model, the PSO model has better accuracy in simulating the air bearing film. Second, the PSO model has a simpler mathematical formulation than the FK model. Third, the PSO model has higher accuracy and requires less computation time than other models including the FK model.