Experimental investigation of centrifugal slurry pump casing wear handling solid-liquid mixtures

The rotating and stationary components of a centrifugal slurry pump develop complex flow field due to suspended solids in the liquid. An uneven wear of the wetted parts of the pump components was reported due to different particle impact conditions like the direct, random and directional. The present work is focused to investigate the erosive wear profile of the pump casing experimentally and its relationship with numerically simulated flow field to establish the effect of dominating factors affecting the erosion of the pump casing at different operating conditions. Experiments were conducted in a pilot plant test rig with two equi-sized sand particulate slurries at two pump speeds and two flow rates. Wear specimens (1.5 x 1.5 x 0.01 cm³) of AISI 304L steel were affixed at different locations along the centerline of the casing wall. The erosion of the specimens was determined based on the measurement of weight loss to study the wear pattern along the casing. Scanning electron microscope (SEM) images of worn out samples were also examined in each case to investigate the material failure at different locations. Further, the flow field inside the pump has been numerically simulated to correlate the particle impact condition with the measured wear. Efforts have been made to identify the dominant mechanism of erosion at different locations of the casing. It was observed that the wear at the volute tongue is contributed by both the cutting and deformation whereas, at all other locations, the material is removed due to cutting and ploughing.