DMST Investigation of the Effect of Cambered Blade Curvature on Small H-Darrieus Rotor Performance

Abstract

A Double Multiple Stream Tube (DMST) model has been carried out in order to investigate the effect of the leading-trailing blade edge curvature on the performance of a small H-Darrieus rotor vertical axis wind turbine (VAWT). Four shaped blades (linear, concave, convex and semi-convex) with cambered airfoils profile (NACA4312) are considered in this study. The reliability of the DMST model has been demonstrated through good agreement between the calculated and measured efficiency of an H-Darrieus. The VAWT performance is primarily investigated according to tip speed ratios, aspect ratio and solidities. The numerical results showed that leading-trailing edge (LTE) curvature has substantially enhanced the turbine’s efficiency at large range of TSR. As compared to straight LTE, up to 31.58% of the performance increases in concave blade shape with 61.85% of mass reduction, up to 23.16% of improvement is found in semi-concave blade shape with a mass reduction of 23.16% and up to 15.8% of efficiency improvement with a mass reduction of 7.45%.