Free-shape modeling and optimization for straight channel of cold plate involving passage pattern, cross-section, and twist of channel

Abstract

To improve flexibility of design and cold plate performance, a novel free-shape modeling method with conventional and rational Bernstein-Bézier functions is proposed. In this study, straight channel models with single and double channels are utilized to verify the proposed method. Both models can be regarded as the basic structure of a cold plate system. Firstly, the dimensions of channel are liberated as several degrees of freedom in the problems of passage pattern (or centerline), cross-section and twist of channel, and these degrees of freedom are mathematically defined by conventional and rational Bernstein-Bézier functions. Herein, three rules are proposed to describe the twist of channel. After that, the optimizations are implemented, and the obtained control coefficients of degrees of freedom are specified as the design variables. The average temperature and root mean square temperature of objective surfaces are defined as objective functions, and they are coupled as a decomposition-based multi-objective function. Besides, the step-by-step optimization strategy is applied to the double channels model in order to reduce the dimensionality of design variables and improve the optimization robustness. Through numerical calculation and experimental verification, it can be found that the optimised designs obtained by optimization can further enhance heat transfer capacity of cold plate. For the average temperature, the highest drops in the SC and DC cases are 7.21 K and 15.56 K, respectively, and for the root mean square temperature, the values are 2.22 K and 1.97 K, respectively. The proposed method can construct the arbitrary centerline, arbitrary cross-sections, and free-spiral channel, which can guide the cold plate design from the passage pattern, cross-section shape, and secondary flows. Furthermore, this method is not only applied to the cold plate design, but also to other tube structure deigns.