Design, Manufacturing and CFD Analysis of Diffuser Augmented Wind Turbine Incorporating Bio-inspired Leading-edge Tubercles

The main purpose of the research work was to design and manufacture a prototype diffuser augmented wind turbine (DAWT). Leading-edge tubercles were incorporated into the design to delay the stall at higher angles of attack and to improve the aerodynamic characteristics of the rotor. Since they create a vortex on the upper edge of the tubercle, these vortical systems impose a backward deflection over the crests of tubercles of the airflow (downwash). This downward deflection delays the airfoil from stalling. On the opposite, there is a net upward deflection of airflow in the troughs of these systems (up wash). The CFD analysis of the rotor was performed to find the torque produced which was used in calculating the power of the wind turbine. The CFD analyses of the brimmed diffuser for various brim heights and diffuser angles were performed and the design giving the maximum power augmentation was selected. A comparative study was performed and the improvements in the power and RPM for the modified blades were logged down. An increase in lift to drag ratio, increase in stall angle and reduction in vibrations were observed in modified blades. The tests of modified blades with brimmed diffuser were also conducted and a power augmentation factor of 2.08 was observed.