混合流态下高速径向动静压轴承静特性分析

Static Performance Analysis of High Speed Hybrid Bearings under Mixed Flow State

以具有深浅腔的高速动静压轴承为研究对象,分析在计入润滑油黏温特性时高转速下油膜层流、紊流共存时的混合流态对油膜特性的影响;建立层流、紊流共存时油膜的Reynolds方程、能量守恒方程、润滑油黏温特性方程以及相应的边界条件,综合利用有限元法和差分法求解以上方程,得出不同工况下油膜的特性参数。结果表明:在一定转速范围内,轴承内部油膜紊流区域随着转速的升高而增大;相同工况下混合流态模型计算出的油膜特性数值大于层流状态模型计算出的数值,数值之差随着转速的升高而增大,因此,高转速引起的润滑油膜流态的变化对轴承特性有一定的影响,在计算轴承特性时,考虑油膜流态的改变有利于得出与实际工况相近的理论数值。

The influence of different flow state on the performance of high speed hybrid bearing was discussed by considering the viscosity-temperature characteristic of lubrication oils.The Reynolds equation under laminar and turbulence flow, the energy conservation equation, the viscosity-temperature characteristics equation of lubrication oils and the corresponding boundary conditions were set up.The performance characteristics of oil film under different operating conditions were obtained by solving these equations with finite difference method and finite element method.The results show that, at a certain speed range, the turbulent area of oil film is increased with the speed rises ; the value of oil film characteristic cal- culated by the mixed flow state model is bigger than that computed by the laminar flow state model, and the difference of two models is increased with the speed rises.Accordingly ,the transformation of oil film flow state caused by high speed has a certain impact on the performance of hybrid bearing, and the change of oil film flow state should be taken into account when calculating the characteristic of hybrid bearing, in order to get theoretical value which is close to actual condition.