Development of small wind turbines for moving vehicles: Effects of flanged diffusers on rotor performance

The main object of this research is to develop a shrouded, small, horizontal-axis wind turbine for moving vehicles. Specifically, this study investigates the effects of flanged diffusers on rotor performance of small (30 cm rotor diameter) wind turbines with different rotor solidities (20-60%) and wind speeds (10-20 m/s). The experiments are conducted in a wind tunnel with and without a flanged diffuser. Results show that the flanged diffuser may significantly increase the power output, torque output, and rotor rotational speed of the wind turbine, largely depending on rotor solidity and wind speed. The higher the solidity and wind speed are, the smaller the effect of the flanged diffuser is. The 30%- and 40%-solidity rotors generate the largest power and torque outputs, respectively, while the 60%-solidity rotor has the lowest rotor rotational speed among the test rotors. These results provide some useful information when considering rotor-generator matching problems and the selection of rotor solidity for moving vehicles. This study also shows that a small wind turbine has the characteristics of low torque and high rotor rotational speed, and high rotor solidity for maximum power output compared to a conventional large wind turbine. (C) 2012 Elsevier Inc. All rights reserved.