Finite blade functions and blade element optimization for diffuser-augmented wind turbines

Abstract Placing a diffuser around wind turbine can increase its power output, but not all mechanisms by which the alters aerodynamics have been investigated thoroughly. Here, we concentrate on one such mechanism: effect of finite number blades. In nearly blade element analyses turbines, effects are approximated Prandtl’s “tip loss factor” goes to zero at tip. We argue that this limiting behaviour cannot be correct for axial velocity in presence diffuser. provide alternative “finite functions” preserve limit velocity, do alter conventional circumferential velocity. maximizing output diffuser-augmented turbine, change function has large impact power-producing region near tip: it increases both chord and an optimized blade. Further, appears make less sensitive tip speed ratio than bare turbine.