Optimization of power generation from shrouded wind turbines

In recent years, a number of studies have shown that shrouded wind turbines can generate greater power compared to bare turbines. The objective of this study is to determine the potential of shrouded wind turbines for increased power generation by employing numerical simulations. An analytical/computational study is performed by employing the commercial Computational Fluid Dynamics (CFD) software FLUENT. An actuator disc model is used to model the turbine. The incompressible Navier-Stokes equations and a two equation realizable k - ε model are employed in the calculations. Power coefficient and generated power are calculated for a large number of cases for horizontal axis wind turbines (HAWT) of various diameters and wind speeds for both bare and shrouded turbines. The design of the shroud is optimized by employing a single objective genetic algorithm; the objective being the maximization of the generated power and power coefficient Cp (power generated by the turbine/kinetic energy of the wind facing the turbine swept area). It was found that the shroud indeed increases the generated power and Cp beyond the Betz's limit; this effect is consistent with that found in the recent literature that the shrouded wind-turbines can generate greater power than the bare turbines. The optimized shape of the shroud or diffuser further increases the generated power and Cp.