Finite-element coupled analyses of the Reynolds and Hagen-Poiseuille equations to calculate pressure and flow of fluid dynamic bearings with a recirculation channel

A finite-element analysis was proposed to evaluate pressure, flow, friction torque, and load capacity of coupled fluid dynamic thrust and journal bearings (CFDBs) with a recirculation channel (RC). The numerical program was developed to simultaneously solve the discretized equations of Reynolds lubrication for the CFDBs and the Hagen-Poiseuille flow for the RC. The proposed method was validated using a two-step procedure. As a first step, the measured flying height was compared with the simulated height. As a second step, pressure, friction torque, and flow calculated from the proposed method were compared with those calculated using computational fluid dynamics software. These results confirmed that the proposed method can effectively predict performances of the CFDBs with an RC.