Hybrid airfoil design method for multi-angle of attack condition in icing wind tunnels

To break through the limitation of airfoil size in icing wind tunnels, a new hybrid airfoil design method is proposed.Compared with other hybrid airfoil design methods, the most significant advantage of the present method lies in its capability to simulate the ice shapes of the original airfoil at different angles of attack with only one set of hybrid airfoil. This method is multi-element airfoil oriented. The shape of the main airfoil, and the position and deflection angle of the flap are designed according to the icing test conditions such as the angle of attack and so on. The change of the position and deflection angle of the flap ensures the consistency of the pressure on the nose section between the hybrid and original airfoils at different angles of attack, which in turn ensures the consistency of ice shapes on the nose section. The chord length of the obtained hybrid airfoil is nearly 40% smaller than that of the original one. Ice shapes of both the hybrid and original airfoils are acquired on two-dimensional airfoil models in an icing wind tunnel.Test results indicate that the ice shapes of the two-dimensional section of the hybrid airfoil are basically the same as those of the original airfoil at multiple angles of attack. Therefore, the proposed hybrid airfoil design method is effective to simulate the icing shape of the original airfoil at different angles of attack.