The Influence of Swirl Brakes on the Rotordynamic Forces Generated by Discharge-To-Suction Leakage Flows

Increasing interest has been given to swirl brakes as a means of reducing destabilizing rotordynarnic forces due to leakage flows in new high speed rocket tur-bopumps. Although swirl brakes have been used suc-cessfully in practice (such as with the Space Shuttle HPOTP), no experimental tests until now have been performed to demonstrate their beneficial effect over a range of leakage flow rates. The present study investi-gates the effect of swirl brakes on rotordynarnic forces generated by discharge-to-suction leakage flows in the annulus of shrouded centrifugal pumps over a range of subsynchronous whirl ratios and various leakage flow rates. In addition, the effectiveness of swirl brakes in the presence of leakage inlet (pump discharge) swir