Suction Performance and Internal Flow of a 2-Bladed Helical Inducer with Inlet Asymmetric Plate

It has been found in our past studies that the installation of asymmetric plate at the inlet of inducer is effective for the suppression of cavitation surge phenomenon.In the present study,the suction performance of 2-bladed helical inducer with an inlet asymmetric plate is experimentally investigated.It is observed that the suction performance in large flow rate conditions is not significantly influenced by the asymmetric plate,whereas the head of inducer with the asymmetric plate increases just before the head breakdown in partial flow conditions.To understand the mechanism of this additional head,the flow measurements and the numerical simulations are carried out.It is found that the circumferential component of absolute velocity at the exit of inducer slightly increases with the development of cavitation in both cases with and without the inlet asymmetric plate,indicating the increase of the theoretical head.The theoretical head increase with the inlet asymmetric plate is also confirmed by the unsteady numerical simulations,suggesting that the additional head is achieved through the increase of the theoretical head with the change of the exiting flow from the inducer associated with some amount of cavitation.