烟气冷凝换热是工业烟气余热回收过程的重要方法之一。本文建立错排管束冷凝换热模型,通过数值模拟方法研究入口速度、入口温度、入口水蒸气体积分数对烟气冷凝换热的影响,并利用场协同原理对换热过程进行深入分析,以揭示速度场、温度场与冷凝水分布之间的耦合特性。结果表明,在湍流状态下,入口速度从1m/s增加到4m/s,入口温度从383K增加到413K,入口水蒸气体积分数由17%增加到32%时,传热系数分别增加66.4%,73.7%,90.8%；热流密度分别增加95.8%,101%,66.6%,均有利于换热；前排管壁换热效果最好,前排管束迎风面换热最强,其传热系数最高可达背风面的3.91倍；同时对多物理场进行协同分析,表出各物理场之间的强耦合特征,在冷凝过程中,迎风侧的换热强度较为稳定,且在中间时刻达到峰值。此外,协同角分析表面,在不同入口条件下,迎风面协同角小于背风面,分别随着入口速度、温度及蒸汽含量的增加而减小了2.7°,1.78°和2.3°。研究成果可为管束换热器的设计选型以及烟气余热回收提供参考。

Flue gas condensation heat transfer is one of the key methods for industrial flue gas waste heat recovery. In this study, a staggered tube bundle condensation heat transfer model was established, and numerical simulations were conducted to investigate the effects of inlet velocity, inlet temperature, and inlet steam volume fraction on the condensation heat transfer performance. Furthermore, the field synergy principle was applied to deeply analyze the heat transfer process and reveal the coupling characteristics among the velocity, temperature, and phase change fields.The results show that under turbulent conditions, increasing the inlet velocity from 1?m/s to 4?m/s, the inlet temperature from 383?K to 413?K, and the inlet steam volume fraction from 17% to 32% led to increases in the heat transfer coefficient by 66.4%, 73.7%, and 90.8%, respectively, and increases in heat flux by 95.8%, 101%, and 66.6%, respectively—all of which are beneficial to heat transfer. The front-row tube surfaces exhibited the best heat transfer performance, with the windward side showing the strongest effect; the maximum local heat transfer coefficient on the windward side was up to 3.91 times that of the leeward side.Multiphysics synergy analysis revealed strong coupling characteristics among the physical fields. During the condensation process, the heat transfer intensity on the windward side remained relatively stable and reached its peak during intermediate stages. Additionally, synergy angle analysis showed that under varying inlet conditions, the synergy angle on the windward side was smaller than that on the leeward side and decreased by 2.7°, 1.78°, and 2.3° with increasing inlet velocity, temperature, and steam volume fraction, respectively. These findings provide theoretical support for the design and optimization of tube bundle heat exchangers and flue gas waste heat recovery systems.Keywords: combined cycle, supercritical, subcritical, steam parameter, cycle efficiency.

北京市自然科学基金资助项目（3194046）;宁夏回族自治区重点研发计划项目（2019BFG02016）