Abstract
A major limitation for the full utilization of wind turbines as the main power source is the large variation of wind availability from one area to another, especially at locations with low average wind speeds. Harnessing energy from the wind using diffuser augmented wind turbines or wind concentrators (commonly called wind lens) is one of the trending topics in the field of wind energy where low wind speed is encountered. The main objective of the present work is to investigate the performance of a new type of wind concentrator composed of multi element airfoil sections. Comparison of the new design is made with common design of wind lens to find the optimum configuration that outperforms a conventional wind lens. The proposed design also allows for extra air flow to pass into the lens between the two elements. This allows the application of dual rotor wind turbine with the wind lens where a second rotor is placed at the exit section of the lens. The performance of the new design was examined using CFD technique via the commercial software ANSYS FLUENT. The study investigated the tilt angle of the front piece, the tilt angle of the back piece as well as the gap between the two sections on the mass flow rate through the lens throat and exit sections. The results of the mass flow rate and wind velocities as well as the drag coefficient are compared with conventional wind lens results. The results show that it is possible to increase the mass flow rate through the throat section by 48.3% in comparison with freestream mass flow rate. The results indicated the possibility of enhancing the mass flow rate through the exit section by 14% higher than that at lens throat. The drag coefficient of the multi element wind lens is 17% lower than that of the conventional wind lens with brim.
