Lock-up characteristics of floating ring seals considering rotor whirling motion:

This paper presents a lock-up condition with rotor whirling motion to predict the lock-up area for floating ring seals in liquid turbopumps. To calculate the hydrodynamic forces with arbitrary rotor motion, bulk flow model is modified with explicitly considering the squeeze velocity and temporal inertia. Finite element method is implemented to solve the transient nonlinear model. The effect of lock-up position on leakage and rotordynamic coefficients of floating ring seals is studied and shows insensitivity to eccentricity within moderate eccentric area (<0.5), which indicates that predicting lock-up area with the lock-up condition is feasible for application. With circular trajectory of rotors, the effects of rotor whirling radius and friction force on lock-up area are investigated. The results show that the lock-up area shrinks toward rotor whirling center, with the increase in the rotor whirling radius and decrease in the friction force. Further, a coupled method of rotor trajectory and floating ring s...