Investigating horizontal-axis wind turbine aerodynamics using cascade flows

The simplest aerodynamic model of horizontal-axis wind turbines is the blade element momentum theory, which assumes that blades behave as airfoils, but a correct two-dimensional representation an infinite cascade lifting bodies. This study analyzes conventional and impulse forms forces on cascades airfoils at spacings pitch angles typical turbine applications. OpenFOAM software was used to simulate steady, incompressible flow Reynolds number 6×106 through NACA 0012 airfoils. force equations agree well (less than 1% error) with determined directly from for four spacing ratios. We concentrate “wake vorticity” term, ignored in analysis. At angle 90°, this term balances viscous drag when attack zero. zero pitch, models outer region high tip speed ratio, can account 27% axial thrust about 4°. normal equation, like angular equation turbines, has no body contribute circulation wake. It shown airfoil assumption conservative elements have higher lift-to-drag ratios same attack. An associated result separation occurs compared airfoil.