A detailed investigation of a novel vertical axis Darrieus wind rotor with two sets of blades

Abstract

The lift-type vertical axis wind turbine (Darrieus rotor) is considered to be a promising device for harnessing wind energy due to its potential advantages. Traditionally, a standard Darrieus rotor has a single ring of airfoils (two or three airfoils) that spins about a vertical axis and has low starting torque. A few researchers have stated that the Darrieus rotor with two sets of blades is likely to improve not only the starting ability but also the power coefficient. However, they have not provided sufficient evidence to support their statement. Thus, in this paper, we conducted a detailed computational fluid dynamics (CFD) investigation on the characteristics (e.g., power output, static torque, vortex, and pressure contours) of this rotor with two sets of blades. The effect of the distance between the outer and inner blades on the performance of this rotor was also discussed and quantified. The findings of this paper are expected to help in developing this new type of Darrieus rotor and offer valuable suggestions for real field applications.