球面螺旋槽动静压气体轴承稳态承载力分析

摘要

建立半球螺旋槽气体动静压轴承润滑分析数学模型；通过建立广义坐标系并进行保角变换简化数学模型，利用广义斜坐标变换划分求解域球面网格，提高数值计算精度；采用有限差分法对控制方程离散，建立控制方程的差分表达式，并采用VC＋＋6．0编程计算三维微气膜稳态气膜厚度和压力分布；通过对微气膜周向和径向压力积分，求得轴承稳态的承载能力；研究动压和静压的耦合效应，分析螺旋槽结构参数、节流孔的数量对轴承承载力的影响规律。结果表明：随着小孔个数的增加，静压效应显著增加，轴承的承载力明显增加；随着螺旋角、槽深比、槽宽比的增大，轴承的承载力均先增大后减小，表明通过轴承优化设计参数可改善气体的润滑特性，提高承载力。%The mathematical model for the lubrication analysis of spherical spiral grooved hybrid gas bearings was estab⁃lished.Through the establishment of the generalized coordinate and conformal mapping,the model was simplified.By gener⁃alized helical coordinate transformation,the solving domain spherical grid was divided,and numercial calculation accuracy was improved.Reynolds equation was discretized by the finite difference method. The differential expression of Reynolds equation was established.The three dimensional (3D) micro steady state gas film pressure distribution and film thickness distribution was calculated by the VC++6. 0 software.The steady state bearing capacity was obtained by the integration of the micro gas film circumferential and radial pressure.Dynamic pressure and static pressure coupling effect was researched. The influence of the spiral groove structure parameters and the number of the orifice variations to bearing capacity was ana⁃lyzed.The result shows that the effect of static pressure is increased notably with the increasing of the number of small holes,as well as of the bearing capacity.Along with the increasing of spiral angle,trough depth rate,trough width ratio,the bearing capacity is all increased first and then decreased,indicating that optimization of gas bearing design parameters can improve the lubrication performance of gas and bearing capacity.