Effects of polyethylene-oxide solutions on the performance of a small propeller

Abstract

The thrust and torque were measured and the efficiency calculated for a 14.6-cm diameter, two-bladed propeller in aqueous solutions of polyethylene oxide, WSR-301, with concentrations ranging from 0 to 75 wppm (weight parts per million). The full operating range of the propeller was studied. For the propeller operating under heavily loaded conditions, the thrust decreases with increasing concentration while the torque passed through a minimum at 10 wppm. This resulted in an increase in efficiency ( p=vr/Qw, where V is the speed of advance, T is the thrust, Q is the torque, and w is the angular frequency of rotation) of up to 10% at 10 wppm. For the propeller operating under lightly loaded conditions, the polymer had little effect on performance. If these results are applicable to full-sized propellers, drag-reducing polymers would not effect propeller performance significantly. Acoustic measurements were also made and they indicate that the polymer has no effect on the strength of the discrete components of the radiated propeller noise.