Geometric design with polynomial method for large deflection angle blades of transonic contra-rotating turbine

It's very difficult to design transonic contra-rotating turbine blades because of its large flow deflection angle character. The paper mainly discusses how to design contra-rotating turbine large deflection angle blades with high order polynomial method. This method keeps the main dynamic performance design parameters unchanged, such as pitch, unguided turning and throat. But the aims of controlling the distribution of gas velocity in the supersonic large deflection angle cascade and restraining the shock produced and its intensity can be achieved by adjusting and optimizing the other subsidiary parameters, and controlling the curvature of both pressure side and suction side and the passage convergence of cascade. The numerical experiments show that the high order polynomial analytic method can be used to design high performance supersonic large deflection angle preliminary profiles.