Three types of liquid annular seals were designed for the front shoulder seal of a liquid oxygen turbopump, which include a hole-pattern seal (HPS), a double helical-groove seal (DHG), and a hybrid damper seal (HDS, with hole-pattern on stator and helical-groove on rotor). To assess and compare the leakage and rotordynamic characteristics of the present three types of annular seals under the liquid oxygen medium, a steady three-dimensional (3D) CFD method was developed to predict the seal leakage, based on the Frozen Rotor interface model. A transient 3D CFD-based perturbation method was also proposed to predict the seal rotordynamic characteristics, based on the subdomain method, mesh deformation technique and multiple-frequency elliptical-orbit whirling model. The accuracy and reliability of the present numerical methods were demonstrated based on the experimental data of leakage rates and rotordynamic coefficients for an experimental hole-pattern seal and an experimental helical-groove seal using water as working fluid. The numerical results show that compared with the traditional hole-pattern seal and helical-groove seal, the novel hybrid damper seal possesses the much less leakage flow rate and much better rotordynamic characteristics, so is a desired seal scheme for the impeller shoulder seal.

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