Influence of blades with surface grooves on aerodynamic performance of H-type vertical axis wind turbine

To enhance the aerodynamic performance of the vertical axis wind turbine (VAWT), a method of arranging grooves on the blade surface is proposed. By the orthogonal experimental design method, it is concluded that the groove starting position has the greatest influence on the wind energy utilization Cp. Using the Cp value as a criterion, the optimal groove structure parameters are determined as follows: groove spacing s = 3 mm, number of grooves n = 12, groove width l = 10.0 mm, aperture ratio xi = 0.80, and groove starting position t = 0.4c; increasing the Cp from 37.4% to 48.5%. The normal and lift force of the groove blade are smoother. The maximum tangential force of the groove blade is delayed backward by 10 degrees at an azimuthal angle and the degree of decrease is relatively slowed down, which achieves a drag reduction of about 79.3% at an azimuthal angle of 150 degrees. Further research indicates that arranging grooves on the blade suction side is reasonable. The vortex flow in the groove can restrain the flow separation, improving the VAWT aerodynamic performance. Finally, the VAWT scale model is fabricated for the wind tunnel test, finding that the start-up wind speed of the groove blade VAWT is reduced by 1.875%, and the maximum increase in output voltage and rotation speed is 17.23% and 7.36%, respectively.