旋转与热效应对齿轮箱轴向迷宫密封泄漏特性的影响

Impact of rotating and thermal effects on leakage performance of gearbox with axial labyrinth seal

探索润滑油与理想气体混合介质下齿轮箱密封泄漏机理,分析转子旋转效应和热效应对迷宫密封泄漏特性的影响,研究旋转效应和热效应造成密封系统转子结构变形和流场变化导致密封性能变化的影响规律.研究结果表明:旋转效应和热效应减小了迷宫密封间隙宽度,其中,热效应膨胀变形量高于旋转效应离心变形一个量级;转子转速存在一个阈值(4000 r/min),当转速超过阈值时,迷宫密封泄漏量明显降低,当转子转速为10000 r/min时,相对无旋转工况,泄漏量下降了18.5%;润滑油温度升高,黏度降低,密封结构的泄漏量呈近线性增大,当温度为140°C时,相比温度为40°C工况,泄漏量上升了58.6%;旋转效应和热效应造成流场变化是影响密封系统泄漏特性的主要因素,结构变形是次要因素.

The rotating and thermal effects on sealing performance were analyzed and the calculation model of axial lateral straight-through labyrinth seal was established,in order to explore the sealing mechanism of high-speed gearbox with mixed media of lubricating oil and ideal gas.The influences of structure deformation and flow field on the sealing performance were also studied,which were induced by the rotating and thermal effects.The results reveal that the rotating and thermal effects can reduce the sealing gap.Nevertheless,the thermal-effect-induced expansive deformation exceeded the rotating-effect-induced centrifugal deformation by one order of magnitude.In addition,the rotation speed had a threshold value(4000 r/min).When the rotor rotation speed exceeded this threshold,the leakage loss of labyrinth seal decreased significantly.Compared with the condition without rotation,the leakage loss decreased 18.5%under the rotation speed of 10000 r/min.At the same time,the leakage loss increased linearly with the increment of lubricating oil temperature and the decrease of oil viscosity.When the oil temperature was at 140°C,the leakage loss increased 58.6%in comparison with that at 40°C.The flow filed caused by rotating and thermal effects is the major factor affecting the leakage performance of gearbox sealing system,while the structure deformation is the secondary factor.