Abstract:S-shaped shaft extension pump is an important device for low-lift pumping station. The efficiency of the existing S-shaped extension pump system can not satisfy the users, so it is difficult to be applied to the practice. Based on CFD numerical simulation, an optimization of the traditional S-shaped bend was made, a new S-shaped shaft extension pump scheme was proposed. A whole flow passage of the system was obtained. The results displayed excellent flow characteristics of the system and the axial velocity uniformity at outlet section of the suction passage at different flow rates was over 99.2%;the efficiency of the system was higher than 77.1% from the pump performance prediction which was approved by the model test. The model pump test was conducted in a high accuracy test standed for hydraulic machinery to validate the numerical results. Under the blade angle of -4°, -2°, 0° and 2°, the lifting heads were between 1.7m and 2.0m, and the maximum pumping efficiencies reached 77.1%~78.35%, which met the higher requirements for application in practice. The horizontal S-shaped shaft extension pump system was successfully applied to a pumping station of Gold-Dam water diversion project in Yangzhou City. The field test of pumping station showed that the hydraulic performances of the high efficient planar S-shaped shaft extension pump system for the prototype system and the performance results of the model system test were basically coincident. The pump units were running stably, and vibration and noise were small. The high efficient planar S-shaped shaft extension pump system had advantages in simple structure, compact layout, less occupation of land, large working space, convenient installation and maintenance. The operation cost of the pumping station would be low due to the hydraulic losses of the system were significantly reduced, especially for the long-running pumping station which had effects on energy saving and consumption reducing;and it was convenient to be used in small and medium sized pumping station to implement standardized construction.
