基于CFD的螺旋槽干气密封气膜刚度的计算

Calculations of the Stiffness of the Gas Film of the Dry Gas Seals of the Spiral Grooves Based on Computational Fluid Dynamics (CFD)

应用Gambit软件建立三维螺旋槽干气密封模型,并对其进行网格划分。在相同特定工况下,运用Fluent软件对6种不同气膜厚度的螺旋槽干气密封内部微间隙三维流场进行数值模拟,得到其流场的压力分布及径向压力分布。通过不同厚度的气膜所产生的动压来获得它们的气膜推力,再利用最小二乘法则拟合得到了气膜推力关于气膜厚度的解析式,求得气膜刚度。结果表明,气膜刚度是关于气膜厚度的负指数函数,通过与试验进行对比,证明了利用此函数来求解气膜刚度是正确的。

The three-dimensional model of the dry gas seal of a spiral groove was founded and its mesh was generated using Gambit software.Under the same specific working condition,a numerical simulation was carried out of the three-dimensional flow field of the micro space in the dry gas seal of the spiral groove with six different thicknesses of gas films using Fluent software,the pressure distribution and the radial pressure distribution of the flow field were obtained.The thrust of the gas films was obtained through the dynamic pressure generated through the gas films with different thicknesses,and the analysis expression of the thrust of the gas films about the thicknesses of the gas films was derived through the fit using least square method,and the stiffness of the gas films was obtained.The result shows that the stiffness of gas films was the function of negative index about the thicknesses of gas films.It was concluded that it was correct to use the function to solve the stiffness of the gas films through comparison of tests.