Multi-objective optimization design of the intake duct for a waterjet system

Abstract

An intake duct for a waterjet system is treated to improve the hydraulic efficiency and the outflow nonuniformity together with its perpendicularity. A multi-objective optimization strategy is proposed by incorporating with design of experiments (DOE), computational fluid dynamics (CFD), inverse design method, Kriging model and non-dominated sorting genetic algorithm-II (NSGA-II). Optimal Latin hyper-cube design method is used in DOE to uniformly sample in variation ranges, and global optimization is then conducted by using NSGA-II based on the input-target approximation functions approximated by the Kriging model. Instead of randomly selecting one solution to implement, a technique for ordering preferences by similarity to ideal solution (TOPSIS) is introduced to select the best compromise solution (BCS) from pareto-front sets. Compared with the original duct, the optimized intake duct has a much better outflow quality at the design operation point with a comparative hydraulic efficiency. Thus, the authors believe the proposed method is helpful for optimizing the intake duct.