Experimental study of centrifugal pump as turbine with S-blade impeller

As a hydraulic energy recovery device, pump as turbine(PAT) has been applied widely in the seawater desalination and petrochemical industry. In order to improve the hydraulic performances, the blade inlet angle was redesigned by analyzing the velocity triangle of PAT impeller inlet, and an S-blade was proposed. Then, A new S-blade impeller was obtained by optimizing the impeller in a real case of centrifugal pump as turbine application, and it was compared with the original impeller through experiments. The results show that the efficiency of the new S-blade impeller is around 3% higher than that of the original blade with the fixed flow rate and head. Under the fixed speed, the shaft power of the new S-blade impeller is higher than that of the original blade, and the maximum deviation is 0.75 kW. The study could have important directive significance to blade optimization of PAT.