Numerical Simulation of Clay Slurries With High Yield Stresses in Centrifugal Pumps

Centrifugal slurry pumps are widely used for hydraulic transportation of solids in the mining and dredging industries. The performance of these pumps degrades when handling a slurry flow. The level of complexity increases for a pump handling non-Newtonian (non-settling) slurries, especially when these slurries exhibit a high yield stress. The viscous effect is the primary source of performance loss in non-Newtonian slurries, and this loss is more pronounced in efficiency than in head. In sets of experiments conducted at GIW Industries, Inc. [1], the measured pump performance and pipeline friction loss were captured while testing a phosphate clay slurry at different solids concentrations. This slurry was tested at a range of yield stresses from 100–600 Pa, established by varying the solids concentration. The tested pump was a GIW-LCC-M 80-300 type, featuring a three-vane, closed-shroud impeller with a 0.3-m diameter. A high-fidelity CFD simulation was developed and simulated, with the measured rheology used as an input to the CFD simulations. The simulation results showed a good agreement with the tested performance. The outcome of these simulations could be used as a resource for predicting the pump derate within the testing range, as the results could help in selecting the pump size and determining the power requirement.