Application of nonlinear numerical optimization to the design of turbomachinery part 2: multiple arc airfoil design

摘要

A new design technique for the two dimensional transonic compressor airfoil is presented, in which a non-linear numerical optimization algorithm is combined with a compressible Navier-Stokes flow solver. The total pressure loss and the error ofthe outlet flow angle are chosen as the objective functions. To each objective function, the flow solver is directly used to estimate the most efficient correction direction of the design parameters. The weighed summation of the correction directions isused to determine the correction vector for the next optimization step. Also, the optimization is accelerated by directly adjusting the camber angle to the flow angle.The new design system is applied to the multiple circular arc airfoil (MCA). Three examples show that, within only ten steps, the total pressure losses and the error of the outlet flow angles are greatly reduced.