低液气比混合润滑下的动压密封性能分析

Analysis on Hydrodynamic Sealing Performance under Low Liquid-gas Ratio Mixed Lubrication

针对小液滴均匀分布在气相中的两相润滑状态下的密封工况,建立气液混合物理模型,推导气液两相混合流体的等效黏度,建立气液混合润滑动压密封端面间的气液混合润滑Reynolds方程。利用MATLAB软件编写有限元程序求解气液混合润滑Reynolds方程,得到动压密封端面间气液混合流体的压力分布及密封性能参数,并分析在操作工况一定时,液气比对密封性能的影响。分析结果表明:在相同的膜厚下,液滴增强了端面流体动压效应;动压密封在运转过程中,端面密封间隙、摩擦功耗和质量泄漏率随液气比的增加而增加,体积泄漏率随液气比的增加而减少,而刚度随液气比的增加先增加后降低,存在最大值。

Under the condition of small liquid droplets distributed in the gas phase uniformly,the gas-liquid mixed physical model was set up,the equivalence viscosity expressions was deduced,and the gas-liquid mixed lubrication Reynolds equation was built. A finite element program was compiled to solve the gas-liquid mixed lubrication Reynolds equation to obtain pressure distribution and sealing performance parameters of gas-liquid mixed fluid between the seal faces. The influence of liquid-gas ratio on the sealing performance was analyzed under the same operating conditions. The analysis results show that the hydrodynamic effect is enhanced because of the liquid droplets at the same film thickness. The seal face clearance,friction power consumption and mass leakage are increased and volume leakage is decreased with the increasing of liquid-gas ratio under the operation conditions of constant speed,pressure and closing force. The fluid stiffness is firstly increased and then decreased with the increasing of liquid-gas ratio,there exists a maximum value for fluid stiffness.