Evaluation of a Potential Flow Model for Propeller and Wind Turbine Design

Abstract

A three-dimensional, potential flow based, unsteady panel code was used to model the flow over rotating propeller blades. It is assumed that for best performance, flow separations must be avoided on the rotating blades of propellers and wind turbines. In this case, idealized tools such as the one used here are significantly faster and simpler for calculating the surface pressure distribution and the resulting performance parameters. Similar experimental data on the surface pressures and on common performance parameters are widely available on propellers (and less on wind turbines) and, therefore, the validation was performed on a two-blade NACA propeller. In the first part of this study, computed results were validated and were found to compare favorably with the experimental data for a wide range of performance parameters. In the second part of this study, a rotor optimization is performed using a generic rotor blade shape. For simplicity, a rectangular blade with several taper ratios and linear twist was used. The computed results indicate that even with this simple geometry, a more efficient design (than the baseline) is possible. It is concluded therefore that by using this tool more complex blade shapes and customized airfoil sections can be developed, leading to additional improvements in performance and efficiency.