基于场协同原理和NSGA-Ⅱ的扇形穴-梯形肋微通道多目标优化

Multi-objective Optimization of A Trapezoidal-rib and Fan-groove Microchannel Based on the Field Synergy Principle and NSGA-Ⅱ

采用数值方法研究了不同结构参数下扇形穴-梯形肋微通道的流动和传热特性。发现肋高(α)对总热阻(R_(th))和压降(Δp)的影响最为显著;随着α的增大,R_(th)迅速减小,而Δp迅速增大。为获得最优参数,采用响应面法、非支配遗传算法Ⅱ(NSGA-Ⅱ)和相似理想解排序技术(TOPSIS)进行多目标优化。并基于场协同原理和强化传热系数(PEC)对优化前后微通道的整体性能进行评价。结果表明,当R_(th)均为0.1858 K/W时,优化后的微通道的W pp仅为0.0062 W,比未优化的微通道降低了53.38%;当W pp均为0.0132 W时,优化后的微通道R_(th)比未优化的微通道R_(th)降低了13.04%,仅为0.16 K/W。优化后微通道的PEC高于未优化前,当R_(e)=231时,PEC从1.163增加到1.253,增加了7.74%;当R_(e)=631时,PEC最大为1.4515。场协同原理表明,TOPSIS最优微通道的速度场和温度场协同效果最好(FC=0.01889)。

Under different structural parameters,the flow and heat transfer characteristics of TF-MCHS are studied using numerical methods.The results show that the rib height(α)has the most significant effect on the total thermal resistance(R_(th))and pressure decrease(Δp).Asαincreases,the R_(th)of the microchannel decreases rapidly,butΔp increases rapidly.To obtain the best parameter,a multi-objective optimization was performed using the response surface methodology(RSM),non-dominated sorting genetic algorithm(NSGA-Ⅱ),and the technique for order preference by similarity to the ideal solution(TOPSIS).According to the field synergy principle and the performance evaluation criteria(PEC),the overall performance of the microchannel before and after optimization was assessed.The results show that when R_(th)is 0.1858 K/W,the pumping power(W pp)of the optimized microchannel is 53.38%lower than that of the unoptimized microchannel,at only 0.0062 W.When W pp is 0.0132 W,the R_(th)of the optimized microchannel decreases by 13.04%,compared with that of the unoptimized microchannel,at only 0.16 K/W.The PEC of the TOPSIS optimal microchannel is higher than that of the unoptimized microchannel.At R_(e)=231,the PEC increases from 1.163 to 1.253,an increase of 7.74%.At R_(e)=631,the PEC is 1.4515.The field synergy principle indicates that the velocity field and temperature field of the TOPSIS optimal microchannel have the best synergy effect(Fc=0.01889).