Open Collections

Numerical study of the duct shape effect on the performance of a ducted vertical axis tidal turbine

University of British Columbia

The current research focused on the numerical modeling of a three-bladed vertical-axis tidal current turbine using the commercial RANS code, FLUENT. A two-dimensional, incompressible, unsteady solver was used for the simulations in conjunction with a Spalart-Ailmaras turbulence model. This approach proved to have satisfactory accuracy at a reasonable computational cost. The first phase of the research focused on simulating of a free-stream turbine for a range of current velocities and tip speed ratios. The torque and power generated by each blade was recorded as a function of azimuth angle and compared to experimentally measured torque and power. The experiments were conducted in parallel to the numerical work by the research group in the Naval Architecture Laboratory at the University of British Columbia. In the second phase of the research, a simple venturi-shape duct was placed around the turbine to accelerate the flow and consequently increase the torque and power generated. Similar to the first phase of the research, the results were validated against experimental values to obtain sufficient confidence in the accuracy of the numerical model predictions. The last phase of the project focused on the optimization of the duct shape with the goal of increasing the power generated by the turbine’s blades over a cycle. The strategy chosen to improve the duct shape was to keep a constant contraction ratio for the duct and to redirect the flow to achieve a proper angle of attack for the airfoil, especially at the azimuth angles where the torque generated by the blades was low.

Thesis/Dissertation

application/pdf

2008-10-17

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/14704

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/