真空环境下小孔节流式静压气体轴承流场特性与轴承性能分析

Analyses on Flow Characteristics and Bearing Performances of Aerostatic Gas Bearings with Pocketed-orifice Type Restrictor Working in Vacuum Conditions

以真空环境下具有排气系统的圆盘形简单孔式节流静压气体轴承为研究对象,忽略过渡流,将流场分成黏性流和分子流区域,利用基本流动方程,推导出黏性流转变为分子流的临界半径,计算转变位置处的临界压力,纠正了前人在相关研究中部分计算式推导和分析结果错误。在此基础上,研究了临界半径和临界压力之间的相互制约关系,气流通道、气腔压力、气腔大小等对临界半径和临界压力的影响,润滑气体分子直径、质量和温度对特征压力影响和对气腔压力的约束,给出了提高轴承性能需着重考虑的因素,为真空下静压气体轴承的性能计算和设计参数优化提供了参考。

The flow characteristics inside aerostatic thrust bearings with pocketed-orifice type restrictors were analyzed for the bearings working in vacuum conditions.In the analysis,transition flows were ignored and the viscous and molecular flows were considered only to simply the calculation.And the critical radius and critical pressures of viscous flows transition to molecular flows were obtained according to the basic flow equations.Moreover,the errors of calculation formula and results presented by other scholars were corrected.Further,the following issues were studied:relationship between the critical radius and critical pressure;influences of gas channels,air chamber pressures and air chamber sizes on the critical radius and critical pressures;constraints of molecular diameters and masses,temperature to air chamber pressures;factors for improving bearing performances.The results are helpful to performance calculations and design parameter optimizations for aerostatic thrust bearings working in vacuum conditions.