CFD优化火箭涡轮泵间隙密封静动态特性计算模型

CFD Optimized Calculation of Static and Dynamic Characteristics for Annular Seals in Rocket Turbo Pumps

关键词:  涡轮泵  间隙密封  计算流体动力学  泄漏量  动力学系数

Key words:  Turbo pump  Annular seal  Computational fluid dynamics  Leakage  Rotordynamic coefficients

摘要:

Bulk flow模型被广泛应用于计算火箭涡轮泵间隙密封泄漏量和动力学系数，然而半经验性的边界条件和阻力系数会降低模型的准确性。CFD数值模拟近年来被应用于间隙密封的研究，表现出优越的性能，然而瞬态计算动力学系数效率较低。结合两种方法的优势，利用CFD稳态流场分布，计算密封间隙边界条件，同时基于泄漏量相等优化目标，确定Bulk flow模型中阻力系数，并采用有限单元法数值求解优化后Bulk flow方程组。与文献中数值结果对比，数值结果与试验结果更加吻合，主刚度和交叉刚度最大偏差率为10.15%和7.54%。

Abstract:

Bulk flow model are widely used to calculate leakage rate and rotordynamic coefficients for annular seals in rocket turbo pumps. However，semi-empirical boundary condition and resistance factor are detrimental for the model accuracy. Computational fluid dynamics approach has been used to conduct annular seal analysis and demonstrated superiority，while calculating rotordynamic coefficients at large computational time costs. To take advantage of two approach，based on CFD steady flow field results，boundary conditions of bulk flow model were determined，and then resistance factor was obtained with optimization objective that leakage rate was the same of two approach. FE method was adopted to solve optimized bulk flow equations. Compared with results in reference，predictions of the present method had an improved agreement with experimental data，and maximum deviation of direct stiffness and coupled stiffness were，respectively，10.15% and 7.54%.