Improvement in the Efficiency of an Impeller by Projecting the Vane into the Eye

The influence of the vane geometry on the hydraulic losses at the inlet of a centrifugal pump impeller has been investigated in this work. The edge of each vane has been projected into the eye, at different lengths, and the pump characteristics (flow rate, total head, speed and energy input) were measured in each case. Then the overall efficiency of the pump was calculated using the collected data. The tests were run in a closed cycle test rig. A significant increase of the efficiency of the pump can be obtained by projecting the vanes into the eye of the impeller. Also, the total head of the pump increases depending on the length of the projection and the speed of rotation.