PIV test of the flow field of a centrifugal pump with four types of impeller blades

Abstract

\n Flow fields for various impellers were measured using water and a two-phase liquid–solid mixture with a particle image velocimetry system in a centrifugal rotating frame in controlled conditions. After measuring absolute velocity vectors in impeller passages, the vectors were decomposed based on the triangle speed principle and the distribution of relative velocity vectors within the impeller was obtained. Then, the distribution of particles and their influence on the performance of different impellers were analyzed. The following conclusions were made from the comparison of relative velocity vector field: first, the wear on the outlet of blades can be mitigated effectively by reducing the outlet angle of impeller blades; second, the pump with a double-arc-shaped profile had a more uniform and stable flow field distribution and higher performance than that with a single-arc profile; and finally, the “jet–wake” structure can be improved significantly by using impellers with long and short blades, resulting in a remarkable reduction in energy loss and improvement in pump efficiency. We also found that solid particles were mainly distributed at the outlet of the impeller and volute wall, while the concentration distribution of large particles tended to match the pressure surface. This research can provide some theoretical guidance for the design and optimization of two-phase flow centrifugal pumps.