摘要
采用CO_(2)/R41(氟甲烷)混合物作为一种新型的传热工质,建立其在小管径管内冷却过程的物理模型,并通过数值模拟研究了不同压力、管径和混合比例对管内流动传热的影响。通过对比超临界流体模拟中常用的湍流模型,得到RNG模型能更好地应用于超临界混合工质的管内流动传热过程的数值模拟。结果表明压力对CO_(2)/R41混合工质的换热系数影响显著,其工况越接近临界点换热系数越大;超临界混合工质的管内换热系数极值随着管径的减小而增大,2 mm光管的换热系数极大值相较4 mm和6 mm光管分别增加了14.4%和30.7%,并且流动传热的均匀性更好,但是Nu数较低;6.5 MPa下的CO_(2)/R41(20/80)相较于8.0 MPa下的纯CO_(2),其管内最大换热系数提高了26.4%。
CO_(2)/R41(methyl fluoride)was applied as a new heat transfer working media,and its physical model of cooling process in small-diameter tube was constituted.Then the effects of pressure,diameter and mixture ratio on the flow and heat transfer in the tube were conducted by numerical simulation.By comparing the turbulence models generally applied in supercritical fluid simulation,the RNG model can be better applied to the numerical simulation of the flow and heat transfer process of supercritical mixture in tube.The results show that the pressure has a significant effect on the heat transfer coefficient of CO_(2)/R41 mixture.The closer of the condition approaches the critical point,the higher the value of heat transfer coefficient is.The maximum heat transfer coefficient of 2 mm tube is 14.4%and 30.7%higher than that of 4 mm and 6mm tubes,and the uniformity of flow and heat transfer is better in 2 mm tube,whereas its Nu number is lower.The maximum heat transfer coefficient of CO_(2)/R41(20/80)at 6.5 MPa is 26.4%higher than that of pure CO_(2)at 8.0 MPa.
作者
林智博
陶乐仁
虞中旸
邱晗
LIN Zhi-bo;TAO Le-ren;YU Zhong-yang;QIU Han(College of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《化学工程》
CAS
CSCD
北大核心
2021年第9期28-33,共6页
Chemical Engineering(China)
基金
上海市动力工程多相流与传热重点实验室(13DZ2260900)。
关键词
超临界二氧化碳
R41
混合物
对流
数值模拟
supercritical carbon dioxide
R41
mixture
convection
numerical simulation
