Multi-objective optimization of the cooling performance of a mini-channel with boot-shaped ribs in transcritical regions using RSM and MOGA

Abstract

Microrib is a promising structural optimization method proposed in heat transfer research project of scramjet regenerative cooling channels. In this article, a new type of boot-shaped microribs was designed to enhance the heat transfer performance in mini cooling channels for transcritical n-Decane. Response Surface Methodology (RSM) and Multi-objective Genetic Algorithm (MOGA) were utilized to optimize the regenerative cooling channels with boot-shaped ribs. In order to improve the various design variables on the objective functions, a series of flow and thermal characteristics simulations were conducted. Four geometric parameters (h, w, pi and Re) were adopted as the design variables. The average temperature of the heated wall ($\overline{\mathrm{T}}$) and the pressure drop between the inlet and oulet ($\mathrm{\Delta }\mathrm{p}$) were selected as the objective functions. The statistical importance of the regression models for $\overline{\mathrm{T}}$ and $\mathrm{\Delta }\mathrm{p}$ was tested by analysis of variance (ANOVA). Then, the Pareto-optimal fronts were obtained via MOGA. The experimental results indicate that the variables influencing $\overline{\mathrm{T}}$ and $\mathrm{\Delta }\mathrm{p}$ from highest to lowest impact are as follows: Re, pi, h, w. The optimum designing parameters of the regenerative cooling channels with boot-shaped ribs in transcritical regions are found to be h = 0.18 mm, w = 0.05 mm, p = 3.70 mm, Re = 7449.70 mm, corresponding to the minimum values of $\overline{\mathrm{T}}$=912.439 K and $\mathrm{\Delta }\mathrm{p}$ =8485.32 Pa.

Additional information

Funding

The research was supported by the National Natural Science Foundation of China (91641121).