Aerodynamic performance of wind turbines. Final report

Abstract

The state-of-the-art of performance prediction methods for both horizontal and vertical axis wind turbines is presented. Strip theory methods for horizontal axis wind turbines are evaluated for various tip loss models. A comparison of these tip models is developed for the ERDA-NASA MOD-O rotor. The occurrence of multiple solutions in strip theory analysis is discussed and illustrated. The performance of high-solidity turbines such as the Chalk design is also presented. Corrections to the strip analysis techniques are developed and incorporated into the analysis used for conventional horizontal axis wind turbines. The predicted performance of the Chalk Turbines is presented. The configuration and performance of optimum horizontal axis wind turbines are discussed. Optimization schemes are developed and discussed and comparisons with the MOD-O rotor are made. Performance at off-design conditions is also examined. The performance model for the Darrieus Rotor is developed. Both linear and non-linear theories are developed. Multiple solutions are found to occur for Darrieus Rotors in the same manner as occurs for horizontal axis rotors. This flow model is compared to existing experimental data and shown to yield excellent agreement. An analytical model of the flow in a Savonius Rotor is presented.