Influence analysis of blade chord length on the performance of a four-bladed Wollongong wind turbine

The Wollongong wind turbine is a new kind of vertical axis wind turbine (VAWT) with its blades rotated by only 180° for each full revolution of the main rotor. A computational study on the effect of blade chord length on the turbine output performance of a four-bladed Wollongong turbine has been conducted using the commercial computational fluid dynamics (CFD) code ANSYS 13.0. A validation study was performed using a Savonius turbine and good agreement was obtained with experimental data. Both rotating and steady CFD simulations were conducted to investigate the performance of the VAWT. Rotating two-dimensional CFD simulations demonstrated that a turbine with a blade length of 550 mm has the highest power curve with a maximum averaged power coefficient of 0.3639, which is almost twice as high as that of a non-modified Savonius turbine. Steady two-dimensional CFD simulations indicated that the Wollongong turbine has a good self-starting capability with an averaged static torque coefficient of 1.09, which is about six times as high as that of a Savonius turbine.