Among mixed flow pumps used in various applications, movable-blade type mixed flow pumps have advantages, that is, maximizing the pump efficiency and the suction performance by adjusting the blade angle appropriate to the operating discharge flow rate. However, we have experienced the severe cavitation erosion in the impeller of this type of pump. In the present study, we firstly conducted the numerical flow simulation of CFD of the entire pump to examine if it can predict the occurrence of cavitation and the erosion location as well as pump performance. The results were compared with those of pump performance tests and visualization. In addition, on the basis of the pressure distribution obtained by numerical simulation of the impeller alone, we investigated the cause of erosion and the measures to avoid the erosion. Finally, it was reported that the new impeller reflecting the findings was confirmed to be successful; the erosion was avoided as expected.

Recently, the composite propeller has attracted attention. In general, it is well known that the composite propeller is expected to reduce cavitation by deforming in conformity with unsteady flow field variation behind the hull. However, the design method applying such advantages effectively has not been established. Therefore, the authors have been studying how to predict the performance of composite propellers by using Fluid Structure Interaction (FSI) analysis. At the same time, the measuring system by using Combination line CCD camera method has been developed by NMRI. There are several studies on the deformation measurement of composite model propellers, but there is little study about the comparison between FSI analysis results so far. In this paper, we carried out comparisons of the experimental results and FSI analysis. It was confirmed that the calculated results regarding hydrodynamic characteristics and deformation of the propeller blade agree well with experimental results.