Date of Award
Master of Science (MS)
This focus of this research is on the study of the aerodynamic performance of a Looped Airfoil Wind Turbine (LAWT™) using the Computational Fluid Dynamics (CFD) software. The looped airfoil wind turbine (LAWT™) is a patented new technology by EverLift Wind Technology, Inc. for generating power from wind. It takes advantage of the superior lift force of a linearly traveling wing compared to the rotating blades in conventional wind turbine configurations. Compared to horizontal and vertical axis wind turbines, the LAWT™ can be manufactured with minimal cost because it does not require complex gear systems and its blades have a constant profile along their length. These considerations make the LAWT™ economically attractive for small-scale decentralized power generation in rural areas. Each LAWT™ is estimated to generate power in the range of 10 kW to 1 MW. Due to various advantages, it is meaningful to determine the maximum possible power generation of a LAWT™ by optimizing its structural layout.
In this study, CFD simulations were conducted using ANSYS Fluent to determine the total lift and drag coefficient of a cascade of airfoils. The adaptive structured meshes were created using the commercial mesh generating software ICEM. The k-kl-ω turbulence model was used to account for flow in the laminar-turbulent transition region. Given the lift and drag coefficients and the kinematics of the system, an analytical formula for the power generation of the LAWT™ was developed. General formulas were obtained for the average lift and drag coefficients so that the total power could be predicted for any number of airfoils in LAWT™. The spacing between airfoils and the track angle were identified as the key design parameter that affected the power generation of the viii LAWT™. The results showed that a marked increase in total power could be achieved if the optimum spacing between the airfoils was used for a given track angle. The same idea was then applied to study an analogous floating Looped Airfoil Hydro-Turbine (LAHT) which converts the kinetic energy of river streams into electricity. The results showed that each LAHT of the same configuration as LAWT can generate nearly 756% more power than the power generated by the LAWT due to much higher density of water compared to air. Finally, to generate more power from LAWT and LAHT, a new highly-cambered airfoil was studied to generate more lift and drag to generate more power. Thus various parameters of LAWT and LAHT were optimized for generating optimum power.
Ramesh K. Agarwal