The power output of a diffuser-shrouded wind turbine is enhanced significantly by coupling a brim to the diffuser exit plane. A design and a predicting method for aerodynamic performance have been presented by a simple theory. Rotor blades of a model wind turbine were newly designed for a specified brimmed diffuser by using this simple theory and tested in the wind tunnel to verify the design method. The performance was also tested by changing the number of blades and types of brimmed-diffuser. Comparison between the test results and prediction shows that the simple predicting method demonstrates the effects of the blade number and the brimmed-diffuser in some extent. Further improvement of the performance is sueeested.
