Evaluation of Wear Ring Seals for High-Speed, High-Pressure Turbopumps

This paper describes a seal evaluation program for application as pump impeller wear rings for high-pressure, high-speed liquid rocket turbopumps. The principal design requirements were to control the leakage to values consistent with efficiency requirements and to eliminate potential explosions resulting from high velocity rubbing at the required clearances. Two approaches were taken: the first allowed rubbing of rotating labyrinth teeth on stationary, soft compatible inserts; the second utilized hydrostatic seals which maintained a fluid film between the stationary seal and the rotating wear ring.