干气密封的流动数值模拟

在探讨干气密封工作原理的基础上提出了利用流动数值模拟进行干气密封端面设计的一种新方法，即选用三维的纳维一斯托克斯方程作为控制方程，用改进的压力偶联方程组半隐式方法(SIMPLER算法)对方程组进行离散，对干气密封摩擦副之间的气体流动进行了数值模拟。利用该方法不仅求得了计算域内的压力分布，而且还求得了速度分布。计算结果表明，干气密封的开槽区域的密封堰对气体产生泵送作用，增大了密封槽内气体的压力，大大增强了干气密封的开启效应，而密封坝对气体流动起到节制作用。对计算结果进行分析，求得了干气密封的工作点和泄漏量，计算泄漏量与实测值很吻合，相对误差不超过10％，与常用的二维计算方法相比，可得到更为精确的结果，为进行干气密封端面二维、三维沟槽结构的优化设计提供了正确、可靠的理论依据。

Mathematical Simulation of Flow in Gas Face Seals

A novel phenomenological model for the design of a non-contacting gas face seal is developed based on the three-dimensional Navier-Stokes equations to simulate the flow between a pair of wearing faces of a spiral groove gas seal. After simplified in the SIMPLER scheme, the equations became algebra equations and could be solved by means of computer code. Both profiles of pressure and velocity could be obtained. And the simulation results showed that the hydrostatic dame section of a gas face seal choked the flow of gas, and the land of hydrodynamic section transferred energy to gas and then increased gas pressure in the groove so that sealing effect could be improved. The operating film thickness and the leakage rate of a gas face seal were determined based on analysis of computational results. It is shown that the calculating leakage rates agree well with the test data for service conditions and the maximal relative error is about 10% so that the developed model might provide a reliable basis for the optimal design of a gas seal.