远临界点垂直管内超临界CO_(2)换热特性的数值模拟研究  

Numerical study on heat transfer characteristics of supercritical CO_(2)in vertical tubes at far-critical points

作　　者：赵崇鑫 崔建波 金延超 韩亚洲 吴龚鹏 何燕[1] 魏振文 ZHAO Chongxin;CUI Jianbo;JIN Yanchao;HAN Yazhou;WU Gongpeng;HE Yan;WEI Zhenwen(College of Electromechanical Engineering,Qingdao University of Science and Technology,Qingdao 266000,China;Qingdao Doright Energy Saving Equipment Company Limited,Qingdao 266000,China)

机构地区：[1]青岛科技大学机电工程学院,山东青岛266000 [2]青岛德固特节能装备股份有限公司,山东青岛266000

出　　处：《山东科学》2025年第1期83-95,共13页Shandong Science

基　　金：青岛博士后应用研究项目(QDBSH20220201001)。

摘　　要：超临界CO_(2)在核能发电、太阳能发电、低温制冷、航空航天等领域有着重要应用。目前对超临界CO_(2)管内对流换热的研究大多在临界点温区附近,而在远离临界点高温高压条件下的超临界CO_(2)换热规律尚不明晰。在高温高压下进行了数值模拟研究,探究了质量流量、入口温度、系统压力、热流密度和管径对对流换热系数的影响,并分析了由这些工况变化引起的浮升力和流动加速效应对换热特性的影响。结果表明:随着质量流量、入口温度、系统压力和热流密度的增加,对流换热系数增大;在不同热流密度条件下,流体的对流换热系数差值沿流动方向逐渐扩大;对流换热系数随着管径增大而减小。相较于临界点附近的换热规律,热流密度和管径对对流换热系数的影响存在差异。总体而言,压力对对流换热系数的影响相对较小。该研究对理解和完善超临界流体换热规律、指导高效安全换热器设计具有重要意义和工程价值。Supercritical CO_(2)plays an important role in many applications such as nuclear power generation,solar power generation,cryogenic refrigeration,and aerospace.Currently,the majority of studies on supercritical CO_(2)convective heat transfer in tubes focus on the temperature range near the critical point,while the heat transfer patterns at high temperature and pressure far from the critical point remain unclear and need to be further studied.In this study,numerical simulations were performed to analyze the effects of mass flow,inlet temperature,system pressure,heat flux density,and tube diameter on the convective heat transfer coefficient at high temperature and pressure,as well as the effects of buoyancy and flow acceleration caused by operating conditions on the heat transfer characteristics.The results show that the convective heat transfer coefficient increases with increasing mass flow,inlet temperature,system pressure,and heat flux density.The difference in convective heat transfer coefficient gradually grows along the flow direction under different heat flux densities.Convective heat transfer coefficient decreases with increasing tube diameter.Compared with the heat transfer patterns near the critical point,heat flux density and tube diameter exert different effects on the convective heat transfer coefficient.In general,the effects of pressure on the convective heat transfer coefficient are small.This study provides significant values to understand the law of supercritical fluid heat transfer and guide the design of efficient and safe heat exchanger.

关 键 词：超临界CO_(2) 远临界点 垂直管 换热特性 数值模拟 

分 类 号：TK-9[动力工程及工程热物理]