Computational Investigation of Erosion Wear on Industrial Centrifugal Pump Handling Solid-Water Flows

The Centrifugal pumps handling solid-water mixture are heavily afflicted by erosion occurring due to the transportation of solid particles. Eventually, the erosion leads to degradation in performance and mechanical properties of the pump materials. The objective of present work is twofold; a comprehensive erosion study on three of the common pump materials (Carbon Steel, SS 304 and SS 316) by considering solid-water mixture with two different erodent materials (Silicon Carbide and Silicon dioxide), and to find the critical locations of erosion wear on the pump by utilizing commercial CFD code ANSYS R16.0 Fluent. Numerical simulations on a 3-D model of the pump have been conducted and the erosion rates caused due to erodent (SiC and SiO2) in various parts of the pump namely spiral casing, front Shroud, back shroud and vanes have been calculated for pump materials carbon steel, SS 316 and SS 304 with the concentrations of erodent varying from 5-25 % and at fixed speed of 1450 rpm. Erosion on carbon steel is found to be 1.15-4.16 times higher than the other two steel for all parts at 25 % concentration for SiC erodent material. The corresponding figure for SiO2 is 1.25-2. Further, it is observed that Casing receives 7-13 times higher erosion than Shrouds and 4-7 times higher than vanes for SiC. Whereas, the wear due to SiO2 is found to be around 12-30 times higher than SiC at 25 % concentration. Thus, Carbon steel receives more wear and SiO2 causes more wear over the pump parts. Erosion is not only found to be critically dependent upon pump and erodent materials but also on the interaction of the erodent material with pump material surface. In general, Erosion is found to be increasing linearly with concentration and causing unequal wear at each part of the pump. It is also found that the critical parts for erosion wear of the industrial pumps are where flow suddenly changes direction.