多孔质气体静压径向轴承的可压流动建模及数值求解

Compressible flow modeling and numerical solution for porous aerostatic journal bearings

为研究可压流动下多孔质静压径向轴承的静特性,基于雷诺润滑方程、多孔质达西方程、气体压力-密度方程,建立了多孔质径向轴承的流动模型.提出了一种处理多孔质轴向端面压力边界条件的Laplace-Neumann虚拟节点法,结合有限差分法、松弛迭代法、压力-密度耦合迭代法对流动模型进行数值求解.分析了可压流动下轴承半径间隙和供给压力对静压特性的影响,并与不可压流动计算结果进行对比.结果表明:在同一最小膜厚下,随着半径间隙和供给压力的增大,可压流动与不可压流动的承载能力、质量流量和功耗均增大.可压流动下的承载能力在半径间隙0.01 mm和0.03 mm下小于不可压流动,在半径间隙0.05 mm下大于不可压.可压流动下的质量流量和功耗均大于不可压流动.本研究可为多孔质静压径向轴承的设计及快速计算提供参考.

To investigate the static characteristics of porous aerostatic journal bearings under compressible flow,the flow model of porous journal bearings was established based on the Reynolds lubrication equation,Darcy equation for porous material and gas pressure-density equation.A Laplace-Neumann virtual node method was introduced to address the axial end face pressure boundary conditions of porous journal bearings.This method was coupled with the finite difference method,relaxation iterative method,and pressure-density coupling iterative method for the numerical solution of the flow model.The effects of radius clearance and supply pressure on the static characteristics under compressible flow were examined and compared with the outcomes derived from incompressible flow computations.The results indicate that,at a consistent minimum film thickness,the load capacity,mass flow rate,and power consumption for both compressible and incompressible flows exhibit an augmentation with the increasing values of radius clearance and supply pressure.Under compressible flow,the load capacity at radius clearance of 0.01 mm and 0.03 mm is less than incompressible flow,and at radius clearance of 0.05 mm is greater than incompressible flow.While the mass flow rate and power consumption under compressible flow are greater than those under incompressible flow.This study could provide a reference for the design and fast calculation of porous journal bearings.