Multi-objective optimization of corrugated tube inserted with multi-channel twisted tape using RSM and NSGA-II

A multi-objective optimization of corrugated tube inserted with multi-channel twisted tape (CMCT) is conducted to obtain the optimal performance, using Response Surface Methodology (RSM) and Non-dominated Sorting Genetic Algorithm (NSGA-II). A series of simulation runs are performed to optimize the design variables (Re, y/w, CN) on the objective functions (Nu(c)/Nu(s), f(c)/f(s) and eta). Regression models are obtained in quadratic polynomial forms, and the statistical importance of each term in the models is assessed by means of the analysis of variance (ANOVA). The NSGA II is adopted to obtain the Pareto-optimal fronts. The results show that the most significant factor is the linear term of Re for Nu(c)/Nu(s), and eta, while that for f(c)/f(s) is the linear term of CN. According to Pareto optimal solution, it can be observed the optimum objective functions are Nu(c)/Nu(s) = 3.464 and f(c)/f(s) = 15.44, corresponding design variables are Re = 2034.44, y/w = 3.271, and CN = 5. The optimal design variables against Re are also obtained, which possesses practical significances for designing heat exchanger.