Suppression of Cavitation Instability Phenomena in a Centrifugal Pump with a Fan Type Inducer by Controlling the Inlet Flow Condition with Blade End Plates

Abstract

Industrial turbopumps for pumping liquefied natural gas must ensure stable performance over a wide flow range from the standpoint of operating conditions and maintenance. When a low-solidity fan-type inducer (auxiliary impeller) is attached to the pump to improve its suction performance，instability phenomena caused by cavitation occur at lower flow rates than the design point. A typical example is cavitation surge，a type of self-excited oscillation caused by intermittent volume changes of cavitation. In this study，blade end plates were attached to the inducer for suppressing this instability phenomenon to investigate the suppression effect of pressure oscillation and to visualize the cavitation behavior. Numerical analysis was also conducted to analyze the internal flow of the pump. The results showed with the addition of blade end plates to the fan-type inducer，the pulsation phenomena caused by cavitation could be controlled up to lower flow rates compared to the basic design.