Improving the floating efficiency for the pads in fluid pivot journal bearing

Previous studies have shown that during the operation of a fluid pivot journal bearing (FPJB), almost only the bottom pad floats. The other two pads are not able to float, resulting in no squeeze film damper (SFD) formed in their places. Therefore, the bearing has not yet reached its full advantage. From this situation, the work focuses on studying how to improve the floating efficiency of the pads in FPJB. Based on a thorough study of the hydrodynamic pressure distribution on the pads and related issues, the orifices are placed in the appropriate position to increase the pressure in the recess. According to this proposed method, all three pads reach the floating state during the stable working of the bearing. The numerical model of FPJB in previous studies is applied to evaluate the effectiveness of the proposed solution. The effect of orifice positions on the buoyancy of the pads was then also thoroughly investigated, and results are then provided and discussed. In the case that orifices are in the middle of the pads, only the bottom pad satisfies floating conditions and the other two pads are almost not able to float. The floating effect of the pad increases when the orifice is moved closer to the top of the hydrodynamic pressure. After the orifice's position is adjusted, the recess pressure increases significantly so that the hydrostatic torque increases while the hydrodynamic torque remains unchanged. As a result, all three pads satisfy the floating conditions. The SFD is not only formed, but also reaches a large value, and therefore, the damping will be greatly increased. Then the calculation results are verified based on a comparison with the data in the previous studies. © IMechE 2022.