Experimental and numerical study on erosive wear in a dredge pump impeller

Experimental and numerical studies were carried out to study the serious erosive wear occurs in dredge pump impellers. The erosion rate model of medium coarse sand on high chromium cast iron was summarized from the test of gas driven sand impacting wet plate. During conveying tests in a pump-pipe model system, erosive wear in the impeller under the conditions of conveying dense flow of medium coarse sand was measured. A numerical method, in which multiple reference frames is used to treat the rotation of impeller domain and particle-wall reflection is implemented in relative reference frame, is applied to predict the particle trajectories in the model pump, and the erosion wear on the impeller is solved based on the erosion rate model. The wear predicted by numerical method is of the same order of magnitude as that predicted by experimental method, but is significantly lower than the latter. This may be due to the neglect of the wear in the disk clearance and the intensification of local wear caused by mold casting defects in the numerical prediction.