Performance improvement of a vortex pump based on volute shape modification

Vortex pumps are widely used in many engineering fields because of their small size and high lift head. However, the efficiency of this pump is quite low compared with that of other pumps. Therefore, the objective of the present study is to increase the efficiency of a vortex pump while increasing the head and reducing the power consumption. Numerical simulations are performed to obtain the internal flow pattern of the pump, and the nonideal double-vortex structure appears under all flow conditions. Modification of the volute shape was then proposed to optimize the double-vortex flow pattern, and the results revealed that the trapezoidal-shaped volute greatly improved the internal flow pattern. Additional modifications are proposed to reduce the power consumption of the pump. The experimental results of the optimized model show increase in the head and efficiency of 3.6 m and 3.2% (under nominal conditions), respectively, and a decrease in the power consumption from 10 to 20 W. This work highlights the importance of the volute shape on the performance of vortex pumps; a proper volute diffusion angle effectively suppresses the nonideal double-vortex structure and then avoids unnecessary energy losses.