Investigation of Differential Evolution Algorithm for a Tandem Cascade Optimization

Due to the fact that there are numerous factors and parameters associated to tandem cascade, and upstream and downstream blades have intensive interference and unknown matching correlation, it is difficult to create tandem blades with high performance based on conventional optimization design method. Therefore, developing an optimization strategy that can take into account key parameters of tandem blades is a feasible way to get optimal design of tandem cascade. In the present work, the Sphere and Rastrigin test functions were adopted to compare and analyze five differential evolution modes, and the DE/r2b/2 evolution mode was then obtained, which can be applied to engineering practice. Based on the present evolutionary pattern, the combination the effects of axial overlap (AO), percent pitch (PP), camber ratio (TR), chord ratio (CR) and approximate incidence angle of the rear blade (K b-b ) are considered comprehensively. Thus, the optimization process and strategy are designed, and the optimization objective function is determined. The optimization results show that under the condition of designed Mach number and large angle of attack (AOA), comparing with the original blades, the optimization makes the static pressure ratio of the tandem blades increased by 1.14%, and the total pressure loss coefficient decreased by 6.57%.