Investigation of the effect of air flow slots on horizontal axis wind turbine blade performance.

The positive effects of split on the aerodynamic performances for horizontal axis wind turbines (HAWT) are well-known. The split improves the HAWT performance by affecting its lift-drag forces. This article represents a numerical study using computational fluid dynamics modeling to investigate the split impacts on the HAWT blades. The blades are designed using NREL's S819 profile at the root and NACA 63-415 profile at the main and tip. Chord length and angle of attack are determined by Blade Element Momentum theory. Overall, there are eight wind turbines that are simulated with different angles of the split, their location on the blade surface, width and number of splits. A steady-state turbulent flow and transition SST turbulence model are used for the Moving Reference Frame calculation and Response Surface Optimization method is used to find the optimum split size. The simulation outcomes highlight that single-split blades, especially with a width of 1.5 mm and an angle of 120 degrees, exhibit superior power coefficients. The determined split geometry blade was compared to the non-split blade in sliding mesh model. The results indicate that power coefficients of split blades surpass non-split blades at tip speed ratios between 5 and 8. Overall, the research suggests that strategically implemented airflow splits can enhance energy production, providing valuable insights for optimizing wind turbine designs.