EFFECT OF INLET CONDITION ON CAVITATION PERFORMANCE OF A CENTRIFUGAL IMPELLER WHICH HAS GEOMETRIES SUITABLE FOR A MINI PUMP

摘要

A mini turbo-pump, whose impeller size is around 5～50 mm in outlet-diameter, is in increasing demand for various heat controlling systems. Under those operating conditions, cavitation is likely to appear and to cause unstable operation and performance drop. Thus, the hydraulic performance including cavitation performance is of great importance. In the preceding study, the authors demonstrated that the greater number of vanes, such as twelve, is preferable for a mini impeller, though they didn't discuss the proposal from the viewpoint of cavitation. To treat this issue, the present study is carried out using two 34 mm dia. impellers, one of which is called as Imp. C having twelve long vanes and the other is Imp. C1 having six long vanes and the six short like splitter vanes. In other words, the objective is to clarify the effect of inlet blockage on the cavitation performance experimentally and numerically. Typical results are as follows: (1) Imp. C has a little bit better cavitation performance than Imp. C1. (2) We had better consider not only the inlet blockage but also the flow uniformity at the impeller inlet when we design a mini pump having high cavitation performance.