Experimental study on high-speed centrifugal pumps with a half-open complex impeller

The experimental study is carried out on high-speed centrifugal pumps with a half-open complex impeller, and the effects of geometrical parameters of impeller on the performance of pump are discussed. Experimental results and analysis show that high-speed centrifugal pumps with closed complex impeller can easily achieve stable head-capacity characrastic curve, while the centrifugal pumps with a half-open complex impeller can't. The slope of negatively slopping characteristic curve and head-coefficient increase with blade numbers. The experimental results also show that the axial clearance between pump casing and half-open complex impeller can influences greatly the performance of centrifugal pumps.