双列螺旋槽液膜密封相变现象及性能

Phase change phenomenon and properties of double spiral groove liquid film seals

为了探究相变现象对密封性能的影响规律,通过联立N-S方程与质量输运方程,建立了液膜密封相变模型,使用有限体积法对控制方程进行离散,对双列螺旋槽液膜密封相变现象进行了仿真模拟,获得了液膜流线及相态分布并分析了结构参数对相变区域与密封性能的影响。结果表明:液膜发生相变后物性参数发生变化,密封间隙内流场与端面压力分布发生明显改变。内侧螺旋槽可以提供稳定的开启力并保证密封端面处于较好的润滑状态,但同时导致密封泄漏增加。通过减小外侧螺旋槽槽面宽比、槽台宽比、螺旋角、槽深或增大外侧螺旋槽槽数均可降低密封泄漏量,提升密封性能。

In order to investigate the influence of phase change on sealing performance, a liquid film seal phase change model has been established by simultaneous N-S equation and mass transport equation, the governing equations are discretized using a finite volume method, the phase change phenomenon of double spiral groove liquid film seal is simulated and the influence of structural parameters on the phase change region and sealing performance is analyzed. The result shows that the physical parameters change when the phase change occurred, and the flow field in the seal clearance and the pressure distribution at the end face changed obviously. The inner spiral groove can provide stable opening force and ensure the sealing end face to be in good lubrication state, but at the same time lead to the seal leakage increased. The sealing leakage can be reduced, and the sealing performance can be improved by reducing the ratio of groove width to face width, the ratio of groove width to dam width, spiral angle, and groove depth of outer spiral groove or increasing the groove number of outer spiral groove.