Cavitation aspect and flow pattern in an axial-flow impeller.

The relationship between pump performance and flow pattern under cavitating conditions was investigated using an axial-flow impeller. The flow pattern at the impeller outlet shows a remarkable change due to cavitation. Change in the pump head and the shaft power curves are closely related to the extent of cavitation growth on the suction side of the blades. The change in performance curves due to cavitation is caused by the change in the theoretical pump head brought about by the change in the flow pattern rather than by an increase of impeller loss. Near the tip section, the blade element efficiency shows marked decrease with cavitation growth.