Efficiency improvement of regenerative pump using blade profile modification: Experimental study

Regenerative flow pump is a kind of turbomachine with the ability to generate high heads at relatively low flow rates. Despite having low hydraulic efficiency, regenerative pumps have found many applications in industries due to their simplicity, compact size, low manufacturing costs, and low specific speed. In this paper, an experimental study has been carried out to investigate the influence of impeller blade change on the performance of regenerative pump. To this end, the straight radial blades were changed to curved blades with the same inlet/outlet angles. Three forward curved blade impellers as well as straight radial blade impeller were designed and manufactured. Since the regenerative pump comply with the affinity laws, the results of experimental tests were expressed in nondimensional coefficients. The results showed that by increasing the blade angle to 10°, the efficiency increased and at higher blade angles of 30° and 50°, the efficiency decreased for all flow conditions. The best angle was obtained about 15° by curve fitting to the experimental data at the design flow coefficient