Study of several design parameters on multi-blade vertical axis wind turbine

This paper describes the experimental resultsof a multi-blade vertical axis wind turbine. A vertical axis wind turbine (VAWT) of a diameter of 205 mm with multiple blades is installed in an open-type small-scale wind tunnel with the aim to study the variation of several wind design parameters (i.e., length and angle) the system. This VAWT was tested at various wind speeds of 5 to 30 m/s in steps of 5 m/s. The results show that the efficiency of this system increases with increasing wind velocities up to approximately 25 m/s, after which the efficiency drops rapidly. Moreover, because the system was found to be dependent on various parameters, skew-normal distribution was applied to predict the rotational speed as a function of several design parameters. The use of an equation for predicting the blade tip speed is discussed in this paper. Parametric surveys of the wind blade design are underway to fully understand the aerodynamic characteristics of the VAWT depending on the number, angle of attack, and chord length (W) of the blades. Regarding the efficiency, the performance depends highly on the blade angle and it has a maximum value at 45°, but when the blade angle is set to on 45°, the case of W/R = 0.39 has the highest, around a factor of 7 higher λ comparing with other cases. Regarding the effect of the oncoming wind speed, the ë ratio against the number of blades showed a typical tendency of an increase, a peak in the middle, and a gradual decrease.