Effect of Fine Sediments on the Performance of Axial Pumps

This study presents experimental work done to investigate the effect of fine sediment concentration on the performance of axial pumps. The pump was tested at three different motor speeds of 1000 rpm, 1150 rpm and 1350 rpm. At each motor speed, the pump was tested at three different sediment concentrations by weight of 0%, 2.485% and 8.10%. The sediment used in the investigation consists of a mixture of fine sand, silt and clay (16% fine sand, 38% silt and 46% clay). Results show that the efficiency of the axial pump is negatively influenced by the presence of fine sediments in the flow. As the sediment concentration increases to 8.10% the maximum reduction in axial pump’s efficiency for the range tested reached about 30% for motor speed of 1350 rpm and up to 40% for the lower motor speed of 1000 rpm. The reduction in the efficiency may be attributed to the change in the viscosity of the fluid that required higher torque (hence higher input power) to produce the same discharge. These results provide an evidence of a considerable reduction of axial pumps efficiency when used to pump water with fine sediment of silt and clay. However, further investigation is recommended for commercial size pumps and at different sediment concentrations and different composition of sediment.