Leakage and rotordynamic analysis of a high pressure floating ring seal in the turbo pump unit of a liquid rocket engine

The floating ring seal is often used in an oxidizer and a fuel pump of the turbo pump unit in the liquid rocket engine because the floating ring seal has the ability to minimize clearance without rubbing phenomenon. For the analysis of performance and vibration characteristics of the turbo pump unit with floating ring seals, the exact prediction of the lock-up position of the floating ring is essential to evaluate the leakage and rotordynamic coefficients from the floating ring seal. The governing equations, which are based on the ‘bulk-flow model’, are derived from extending the eccentric annular plain seal analysis. The solution procedure is developed by using the Fast Fourier Transform Method of Nelson and Nguyen. The results of lock-up position, attitude angle of the floating ring, leakage flow rate, and rotordynamic coefficients are presented with operating conditions and geometric parameters of the floating ring seal for an example case.