Abstract: The effects of seal and internal damping on the dynamic stability of liquid hydrogen turbopump rotor system used in rocket engine are studied. The Muszynska model is employed to obtain the nonlinear hydrodynamic forces due to seal, and the nonlinear finite element model of an actual turbopump rotor system is established using Timoshenko beam model including the effect of internal damping. Associated with the shooting method and Floquet theory, the dynamic stability of the rotor system including the effects of seal and damping is analyzed under the stiff and soft support design. Numerical results are in good agreement with prior experimental researches. The effects of bearing damping, axial Reynolds numbers and seal parameters on the critical speed of instability are investigated and the results can be utilized for turbopump rotor–seal system design.

Key words: Internal damping, Seal, Stability Rocket engine, Turbopump