Performance evaluation of cowl-augmented wind turbine

Ducted wind turbines are extremely useful in areas with low wind speeds. The presence of the duct enhances the wind velocity where the turbine blades are fixed. The performance of the ducted turbine mainly depends on the average velocity at the blade plane. The objective of this article is to optimize the duct to enhance the performance of the wind turbine and reduce the net load acting on it. Numerical simulations were performed on four ducts of different configurations (a) plate, (b) plate with the flange at the exit, (c) aerofoil, and (d) aerofoil with the cowl of same aspect ratio using ANSYS Fluent. The performances were evaluated, and it was found that the aerofoil duct with cowl showed improved performance with less net load acting on it and had a high drag coefficient. The geometrical parameters of duct and cowl were optimized using the design of experiments (DOE) approach to improve the speed-up ratio and reduce the drag coefficient. Simulation responses such as speed-up ratio, pressure coefficient, isovolume of pressure, and drag coefficients were taken into consideration. The results indicate that the increase in isovolume of pressure >= 0.5 Pa over the enclosure's pressure side enhances the average throat velocity. The investigations show that the duct L/D ratio was significant in improving the speed-up ratio and volume of pressure, whereas the cowl angle showed dominance in increasing the drag coefficient. The optimum combination of duct and cowl with high speed-up ratio, less net load was concluded.