Wind tunnel test on effects of solidity on performance of vertical axis wind turbine

The solidity is an important factor which affects the performance of vertical axis wind turbine(VAWT).A solidity of small-scale VAWT was studied by wind tunnel test.The test mainly focused on two factors: rotor radius and blade number.Six types of combinations were made and 5 kinds of solidities were obtained that included 3 kinds of rotor radii and 2 kinds of blade numbers.The torque and power performance at a low rotational speed stage after starting were measured and analyzed.The results show that the wind turbine with smaller solidity can get maximum torque and power coefficients when the rotor radii are the same.The tip speed ratios at which maximum torque coefficient occur are almost the same for the rotors with same solidity,but the tip speed ratio becomes larger when the solidity becomes smaller.