Date of Award

8-2012

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Advisor

Michael Peterson Jr.

Second Committee Member

Richard Kimball

Third Committee Member

Krish P. Thiagarajan

Abstract

Energy independence and a reduction on the reliance on fossil fuels is a critical area of current research and development. Utilizing the energy in the world’s oceans can help the world move towards a more sustainable energy supply. One of the most promising sources of ocean energy is tidal energy or marine hydrokinetics, the topic of this thesis. This research analyzes the performance of a ducted axial flow tidal turbine and compares the result to an unducted turbine. While the focus of this research is on experimental results obtained in tow tank tests, the turbine and duct were designed using the open source software code, OpenProp. OpenProp was used because of the suitability of the design approach for the optimization of a turbine design and its modeling capability for ducted propellers. While OpenProp has the capability to analyze ducted turbines this capability has been added only recently and has not been validated. Thus the duct used in the experimental work could not be optimized and was intended to provide data which could be used as a part of the validation of the ducted portion of the code. Literature reviews indicate that limited experimental data exists for the performance of comparable ducted and unducted turbines. The design used is a three-bladed, ducted turbine with blade shapes optimized in OpenProp. For the unducted case, an optimal of 0.44 was measured at a tip speed ratio of 4.43. The duct was shown to have a detrimental effect on the performance of the turbine with a maximum at a tip speed ratio of 4.4. This result demonstrates the challenges associated with the design of an efficient ducted turbine.

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