Wu Zhixiang, Feng Huijun, Chen Lingen, Ge Yanlin
Institute of Thermal Science and Power Engineering, Wuhan Institute of Technology, Wuhan 430205, China.
School of Mechanical and Electrical Engineering, Wuhan Institute of Technology, Wuhan 430205, China.
Entropy (Basel). 2020 Jun 9;22(6):641. doi: 10.3390/e22060641.
Constructal optimization of a plate condenser with fixed heat transfer rate and effective volume in ocean thermal energy conversion (OTEC) system is performed based on constructal theory. Optimizations of entropy generation rate ( S ˙ g ) in heat transfer process and total pumping power ( P sum ) due to friction loss are two conflicting objectives for a plate condenser. With the conventional optimization method, the plate condenser is designed by taking a composite function (CF) considering both S ˙ g and P sum as optimization objectives, and employing effective length, width, and effective number of heat transfer plates as design variables. Effects of structural parameters of the plate condenser and weighting coefficient of CF on design results are investigated. With a multi-objective genetic algorithm, the plate condenser is designed by simultaneously optimizing S ˙ g and P sum , and the Pareto optimal set is obtained. The results demonstrate that CFs after primary and twice-constructal optimizations are respectively reduced by 7.8% and 9.9% compared with the initial CF, and the effective volume of the plate condenser has a positive impact on the twice minimum CF. Furthermore, the Pareto optimal set can provide better selections for performance optimizations of plate condensers.
基于构形理论，对海洋热能转换（OTEC）系统中具有固定传热速率和有效体积的板式冷凝器进行了构形优化。传热过程中的熵产生率（(S˙g)）优化和摩擦损失导致的总泵送功率（(Psum)）优化是板式冷凝器的两个相互冲突的目标。采用传统优化方法，以同时考虑(S˙g)和(Psum)的复合函数（CF）为优化目标，以有效长度、宽度和传热板有效数量为设计变量，对板式冷凝器进行设计。研究了板式冷凝器结构参数和CF加权系数对设计结果的影响。采用多目标遗传算法，通过同时优化(S˙g)和(Psum)对板式冷凝器进行设计，得到了帕累托最优集。结果表明，一次构形优化和二次构形优化后的CF分别比初始CF降低了7.8%和9.9%，板式冷凝器的有效体积对二次最小CF有积极影响。此外，帕累托最优集可为板式冷凝器的性能优化提供更好的选择。
