Study of characteristic curves of rotodynamic pumps working as turbines

Centrifugal pumps working in reverse mode can be a good alternative for conventional water turbines. Prediction of the pumps as turbine characteristic curve is still complicated due to the lack of information provided by the producers and rare research focusing on this subject. In some cases of pumping systems it is important to estimate the operating point in turbine mode basing on pump test data. In this paper the pump characteristics in turbine mode for ten pumps with a specific speed between 10-261 were compared and analyzed. The formulas used to predict the best performance point and characteristics of pump as turbine was reviewed. Own formulas for calculating optimum points of pump in the turbine mode was proposed.