Hydrodynamics performance of the twin blade hydrofoil arrangement for possible applications of wind and hydrokinetic turbines

Abstract

Hydrodynamic performance of a twin-blade hydrofoil in the range of the tip speed ratio from 1.5 to 5.5 has been numerically and experimentally investigated. The geometry of the twin blade hydrofoil is presented in the figure below. FLUENT and ANSYS numerical analysis programs were used in the two and three dimensional analysis respectively. At the design flow velocity of 2 m/s (Re = 3.02x105) the maximum power coefficient of 0.457 was obtained at the tip velocity ratio of 3.5 at an optimum geometric parameters of h/c1 = 0.667, c1/c2 = 0.67 and the angle of attack of 3°. This tip speed ratio is considered to be low comparing others applications such as hydrofoil-slat arrangements and standard hydrofoil applications. Therefore the double blade arrangements can be used in the wind and hydrokinetic turbines to produce electric energies at moderate low wind and hydrokinetic current velocities.