Numerical investigation of the effect of blade tip loading distribution on tip leakage vortex characteristics in a waterjet pump

Abstract

Abstract The blade tip leakage vortex (TLV) is a common concern for waterjet pump. The TLV are closely related to the load distribution at the blade tip. This paper aims at to investigate the relationship between blade tip load distribution and TLV trajectory and size. The characteristics of tip leakage vortex in a mixed flow pump is investigated by numerical method. The SST k-ω turbulence model is used to predict TLV trajectories. The result shows a good agreement with the visualization results based on high-speed photography (HSP), which validated that the accuracy of numerical method. The numerical results show that the starting point of the TLV, as well as the angle between blade chord and TLV changes with flow rate condition, which related with the blade tip loading. Therefore, the distribution of the load at the top of the leaf necessarily influences the trajectory of the leakage vortex. Comparing the three different loading patterns at the blade tip, it can be seen that as the load moves backwards, the starting position of the leakage vortex at the blade tip moves backwards and the relative angle between the TLV and blade increases.