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

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%.