动载工况下滑动轴承油膜边界历史迁移问题

HISTORY MOVING OF CAVITATION FOR DYNAMICALLY LOADED JOURNAL BEARING

通过对Elrod算法进行改进,得到基于质量守恒边界条件的不可压缩流体空穴算法,能用统一方程来描述动载滑动轴承完整油膜区和空穴区的润滑工况,并在此基础上开发了相应的计算手段。该算法通过引入一个中间变量ξ和一个开关函数g,不同区域给ξ赋予不同的物理意义,将完整油膜区的雷诺方程和空穴区的润滑方程统一为通用方程,可自动跟踪动态边界,使质量守恒边界条件能更为简便而精确地应用于轴承计算实际。通过与现有试验结果的比较分析发现,采用不可压缩流体空穴算法的理论计算结果能比较好地描述动载工况下油膜空穴的历史迁移过程,与试验数据能很好对应。同时研究发现,润滑油膜可以承受一定负压,空穴压力大小的选取对理论分析有相当影响。

On the base of the Elrod algorithm, a generalized equation is derived to describe the lubrication in full film region and in cavitation region of dynamically loaded journal bearing, which is nominated as the incompressible mass-conserving cavitation algorithm. A numerical technique with this algorithm has been solved. By the definition of a switch function g and a variable 4, which have different meaning in different zone, a generalized equation is derived to integrate the Reynolds equation in full film region with the lubrication equation in cavitation region. This algorithm can predict the moving oil boundary automatically and make the mass conserving boundary condition （JFO theory） more easily and precisely to be applied in actual analysis. It is found that the analysis results with the incompressible mass-conserving cavitation algorithm have good agreement with the existing experiment data. The incompressible cavitation algorithm can predict the history moving of cavitation well, And it is also shown that the pressure value in the cavitation has great effect on the analysis results.