A Novel Airfoil Design Method and its Application to the Optimization Design of a 3-Stage Transonic Compressor

In this paper, a novel airfoil design method is proposed by introducing multiple physical characteristics to the process of parameterization. The new design method is to operate the camber and thickness distributions in a way that the chordwise mapping information is adjusted without using local geometrical parameters. A proper design space is expected to be constructed, in which the laws of optimization can be simply transmitted from a single airfoil to the whole blade and even stages. The capability of the method is firstly validated in the Pareto optimization of a 2D compressor airfoil, and then specialized for the optimization of a rotor in a 3-stage transonic compressor. The 3-stage transonic compressor studied in this paper is representative of the inlet stages of an industrial gas turbine, and the shock structure of the third rotor (R3) presents the peak strength near the mid span. The optimized design reduces the peak Mach number on the suction surface, and increases the efficiency of the third stage and the whole compressor by nearly 1% and 0.3% respectively. The mechanism of the loss optimization is analyzed in detail.