Propeller Tip Cavitation Suppression Using Selective Polymer Injections

Selective injection of a drag-reducing polymer solution into the tip vortex region of the blades of an 11.5 inch diameter propeller is seen to be effective in significantly delaying tip vortex cavitation. For well positioned injection ports, the cavitation number at inception was decreased by as much as 35 percent. Injections of water and a mixture of water and glycerin for the same conditions did not affect the inception characteristics of the blades. Propeller thrust and lift were not affected at the selective polymer injection rate needed to affect the cavitation characteristics of the propeller.