Computational Fluid Dynamics Analysis of Towed-Water Power Generators

Towed-water power generators are used in long-distance sailing to generate power for charging battery banks. A basic configuration consists of a spinning turbine (propeller) towed behind the boat and attached to an alternator or generator via a torque line. In the present work, a series of seven inch diameter, six inch pitch turbines were tested both on the water and using computational fluid dynamics techniques. Turbine rotation rates for both an alternator and generator charging a 12V, 80 AH battery were measured for the on-water tests at a nominal towing speed of 3 m/s. Turbine torque vs. rotation rate results obtained by solving the Reynolds-averaged Navier-Stokes equations were plotted against generator and alternator torque curves to predict operating rotations per minute and associated power generation. Predicted rotation rate results were in reasonable agreement with those measured on the water.