Multi-objective optimization of internally finned tubes with interruption-and-rotation strategy based on RSM and NSGA-II

Abstract

In the pursuit of compact and high-efficiency heat exchanger designs aligned with carbon reduction goals, this study introduces a novel interruption-and-rotation strategy of internally finned tubes. The design disrupts thermal boundary layer formation through positioned fin discontinuities combined with rotation, thereby augmenting convective heat transfer via intensified fluid mixing. A computational fluid dynamics (CFD) analysis framework was established to evaluate the effects of the interruption start position, interruption length, and rotation angle on flow and heat transfer characteristics. Subsequently, a multi-objective optimization was performed using the response surface method (RSM) and the non-dominated sorting genetic algorithm II (NSGA-II), targeting the minimization of average fluid temperature and pressure drop. The technique for order preference by similarity to ideal solution (TOPSIS) method was employed to identify the optimal trade-off solution. The results indicate that the optimized structural parameters enhance the comprehensive heat transfer performance by 9.32 %, reduce the average fluid temperature by 3.6 % and decrease the pressure drop by 69.2 %, with subsequent numerical verification confirming prediction accuracy within 8.56 % error margin. The design and approach systematically offer new insights into practical enhancement strategies for energy-efficient heat exchange systems in industrial applications.