MEASUREMENT OF FLOW FIELD NEAR A TIP LEAKAGE VORTEX CAVITATION IN A TURBOPUMP INDUCER

Abstract

Flow field near the tip region of a turbopump inducer has been measured using Particle Image Velocimetry (PIV) method in a cavitating condition. Tip leakage vortex cavitation in an inducer leads to hydraulic instabilities, thus, the effects of tip leakage vortex cavitation on a flow field near the blade need to be investigated. Using the tilted laser sheet, flow field near the tip leakage vortex cavitation has been measured. Two different sizes of tip leakage vortex cavitation has been compared. For a small cavitation region, the flow field near the inducer blade is not affected by tip leakage vortex cavitation. Thus, an incidence angle near the leading edge of the inducer blade is positive. On the other hand, for a large cavitation region, tip leakage vortex cavitation increases the axial and absolute tangential velocity near the leading edge of the inducer blade. Thus, the incidence angle becomes negative. Such measurements give clues to understand the mechanism of hydraulic instabilities induced by tip leakage vortex cavitation.