Date of Award

5-2013

Degree Type

Report

Degree Name

Master of Science (MS)

Department

Mechanical and Aerospace Engineering

First Advisor

Robert Spall

Abstract

Computational fluid dynamics can be used to predict operating conditions of towed water turbines which are used in long distance sailing applications to meet electrical demands. The design consists of a turbine fastened to a shaft which is attached to a generator by a rope. The turbine is pulled in water behind a sailboat and torque is transmitted through the rope to turn the onboard generator and produce power. Torque curves from an alternator, generator, and from computational fluid dynamics were used to determine the operating spin rate and output power of the system. On-water tests were conducted to determine the accuracy of the computation fluid dynamics approach. For the on-water tests the revolutions per minute, voltage, and current were measured in water behind a boat and in a 12 inch diameter pipe. Both scenarios were tested with a flow speed of 3 m/s. The results behind the boat were found using both an alternator and a generator while charging a 12 V and 88 AH battery. The values in the pipe were found while connected to heat dissipating dump load resistors. Scenarios of 3.46, 5.46, and 7.46 ohms of resistance were each analyzed while attached to the alternator and generator. The open-water power results consisted of 70 W for the alternator and 41 W for the generator. The results for the in-pipe turbine ranged from 66 to 245 W. Multiple approaches of efficiency of the turbine are considered as well as the efficiencies of an alternator and generator.

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