Optimization of flanges for diffuser casings of diffuser augmented wind turbines

Diffuser Augmented Wind Turbines (DAWTs) are used in harnessing of wind energy in a more efficient way compared to the conventional wind turbines. In this article, the mass flow rate through the shroud is increased by the addition of flanges at the aft of the shroud. Using Reynolds Averaged Navier Stokes Equation along with k-ω SST turbulence models, the flow properties through the diffuser is obtained. The modeling of the diffuser was done using a NACA 9415 Airfoil in CATIA and running the simulations in ANSYS FLUENT. Grid Convergence Study was done for these results prior to further analysis. The flange angle and the height along with the open-angle of the diffuser were optimized for maximum mass flow rate through the rotor plane. The performance of the diffuser has been analyzed in terms of the swallowed mass flow rate, pressure variation along the diffuser and velocity at the rotor plane.