低压CO_(2)/H_(2)O管束外凝结换热数值模拟  

Numerical simulation of condensation heat transfer outside low pressure CO_(2)/H_(2)O horizontal tube bundle

作　　者：曹凤岩 鲁军辉 陈红兵 王岩[2] 王随林 CAO Fengyan;LU Junhui;CHEN Hongbing;WANG Yan;WANG Suilin(School of Environment and Energy Engineering,Beijing University of Civil Engineering and Architecture,Beijing 100044,China;National Key Laboratory of Spacecraft Thermal Control,General Design Department of Beijing Space Vehicle,Beijing 100094,China)

机构地区：[1]北京建筑大学环境与能源工程学院,北京100044 [2]北京空间飞行器总体设计部航天器热控全国重点实验室,北京100094

出　　处：《热力发电》2025年第3期69-78,共10页Thermal Power Generation

基　　金：国家自然科学基金项目(52406063);北京学者计划项目(2015022);北京市教育委员会科研计划项目(KM202310016006)。

摘　　要：碳捕集与封存是实现“双碳”目标的重要途径,超临界水煤制氢耦合CO_(2)/H_(2)O混合工质热力发电系统排气为低压、低温CO_(2)/H_(2)O混合气体,为实现零碳排放及热量回收,冷凝分离CO_(2)/H_(2)O是必要途径。采用Fluent软件模拟了CO_(2)/H_(2)O混合气水平叉排管束外的冷凝换热特性,运用VOF模型、组分输运模型以及利用UDF编写的相变模型加载两相流的质量、能量和组分源项,研究了壁面液膜的形成发展过程和液滴附近流线、速度矢量、液相体积分数的分布,以及速度、蒸汽过热度和不凝气体含量对传热系数和扩散层热阻的影响。结果表明:模拟结果与实验数据相吻合,液膜热阻不随蒸汽过热度变化,但随CO_(2)摩尔分数、入口流速和总压力的升高而减小;混合气体扩散层热阻随CO_(2)摩尔分数和过热度的升高而增大,随入口流速的增大而减小;总传热系数随蒸汽过热度、入口流速和压力的升高而增大,随CO_(2)摩尔分数升高而减小,且局部冷凝传热系数与液膜厚度呈负相关,提出了一种适用于低压CO_(2)/H_(2)O冷凝传热、传质的无因次关联式。Carbon capture and storage is an important way to achieve the“dual-carbon”goal.The exhaust gas of the supercritical water-coal to hydrogen coupled CO_(2)/H_(2)O mixed working medium thermal power generation system is low pressure and low-temperature CO_(2)/H_(2)O mixed gas.In order to achieve zero carbon emission and heat recovery,condensation separation of CO_(2)/H_(2)O is a necessary way.Fluent is used to simulate the condensing heat transfer characteristics of CO_(2)/H_(2)O mixture outside the horizontal bifurcation tube bundle.The volume of fluid(VOF)model,the component transport model,and the phase transition model written by the user-defined functions(UDF)are employed to load the mass,energy,and component source terms of the two-phase flow.The formation and development process of the liquid film on the wall surface,and the distribution of streamlines,velocity vectors,and liquid-phase volume fractions in the vicinity of droplets,as well as the effects of velocity,vapor superheat,and noncondensable gas content on the heat transfer coefficients and the thermal resistance of the diffusion layer,are investigated.The results show that,the simulation results are in agreement with the experimental data,and the liquid film thermal resistance hardly varies with the steam superheat but decreases with the increase of CO_(2) content,inlet flow rate and total pressure.The thermal resistance of the mixed gas diffusion layer increases with the CO_(2) content and steam superheat,and decreases with the increase of inlet flow rate.The total heat transfer coefficient increases with the steam superheat,inlet flow rate and pressure,and decreases with the CO_(2) content,and the local condensation heat transfer coefficient is negatively correlated with the liquid film thickness.A new dimensionless correlation formula for heat and mass transfer of condensation is proposed for low pressure CO_(2)/H_(2)O condensation process.

关 键 词：数值模拟 CO_(2)/H_(2)O混合气 低压 叉排管束 凝结换热 

分 类 号：TM621[电气工程—电力系统及自动化] TK124[动力工程及工程热物理—工程热物理] X701[动力工程及工程热物理—热能工程]