空化效应对斜线槽机械密封性能的影响

润滑膜的空化效应对流体动压型机械密封的密封性能影响显著。以煤油基磁流体润滑斜线槽上游泵送机械密封为研究对象，考虑空化热效应以及黏温效应，建立润滑液膜特性的数值分析模型，以液膜中的气相体积分数为指标，研究工况和结构参数对密封性能的影响规律，并与仅考虑黏温效应的模型进行对比。结果表明：因空化热模型考虑液膜介质饱和蒸汽压力随温度变化，考虑空化热效应时的开启力、泄漏率和气相体积分数均小于仅考虑黏温效应下的对应值，但2种条件下各参数的变化趋势基本一致；转速和槽径比增大，空化效应增强，而进口压力、膜厚、径向夹角和槽数的增大会削弱空化效应；转速、槽深、径向夹角、槽径比增加，会导致泄漏率增加，而进口压力和槽数的增加能够提升密封性能。

Effect of Cavitation on Sealing Performance of Inclined Groove Mechanical Seal

The cavitation effect of lubricating film has a significant impact on the seal performance of hydrodynamic pressure mechanical seals.Kerosene-based magnetic fluid lubrication upstream pumping mechanical seal with inclined groove was taken as the research object.By considering the cavitation heat effect as well as the viscous temperature effect,the calculation model of lubricating fluid film was established to study the influences of working conditions and structural parameters on the seal performances using the volume fraction of gas phase in the liquid film as an indicator,and the results were compared with those based on the model only considering the viscous temperature effect.It is found that,due to the cavitation heat model considering the variation of saturated vapor pressure of liquid film medium with temperature,the opening force,leakage rate and volume fraction of vapor phase when considering the thermal effect of cavitation are smaller than the corresponding results when considering the viscosity-temperature effect only,but the variation regularity of each parameter is basically the same under the two conditions.The cavitation effect is enhanced by increasing the rotational speed and the groove diameter ratio,while the cavitation effect is weakened by increasing the inlet pressure,film thickness,radial angle and number of grooves.An increase in rotational speed,groove depth,radial angle,and groove diameter ratio will lead to an increase in leakage rate,while an increase in inlet pressure and groove number can improve sealing performance.