Abstract
Roto-dynamic pumps can offer attractive performance when coupled mechanically to wind rotors in shallow lift water pumping applications. However, the gearing ratio required in the transmission for such systems restricts their commercial acceptability. This problem can be reduced by selecting a pump with a very low specific speed, so that, for a particular flow and lift, the shaft need not rotate so fast. Therefore, a regenerative pump was designed and developed for wind powered water pumping applications. A semi-empirical approach was adopted for the design. Performance of the pump was evaluated under variable operating conditions. Power-speed characteristics of the pump at different pumping heads were established and superimposed on those of a suitable wind rotor, to identify the points of operation of the integrated rotor-pump system. With optimum gearing, the peak efficiency points of the rotor and the pump could be reasonably matched over a wide range of conditions. Operating speeds of the system at different wind speeds were estimated and then translated into discharge rates and overall system efficiency. The proposed wind pumping system, with the regenerative pump, performs better on shallow lifts than either wind-driven piston or centrifugal pumping systems.