变物性比下无量纲力对超临界压力甲烷混合对流换热影响  

Effects of dimensionless forces on mixed convection heat transfer of supercritical pressure methane under variable thermophysical property ratio

作　　者：姜文全[1] 李琳 杨帆[2] 宿诗雨 石杰峰 李洋 JIANG Wenquan;LI Lin;YANG Fan;SU Shiyu;SHI Jiefeng;LI Yang(School of Mechanical Engineering, Liaoning Petrochemical University, Fushun 113001, China;College of Petroleum Engineering, Liaoning Petrochemical University, Fushun 113001, China)

机构地区：[1]辽宁石油化工大学机械工程学院,辽宁抚顺113001 [2]辽宁石油化工大学石油天然气工程学院,辽宁抚顺113001

出　　处：《中国石油大学学报（自然科学版）》2022年第3期140-147,共8页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(52006094);辽宁省教育厅科学研究经费项目(L2019024);辽宁省博士科研启动基金项目(2021-BS-248)。

摘　　要：采用RNG k-ε湍流模型结合增强壁面函数处理的方法,对竖直上升管内超临界压力甲烷的对流换热进行数值模拟,从物性比的角度进行无量纲力分析,提出适用于低温甲烷的浮升力准则。结果表明高热流密度和低质量流率均会导致拟临界温度附近出现换热异常现象;密度比增大时,浮升力引起的自然对流增强,导致混合对流换热,发生恶化现象,随着密度比减小,黏度降低导致的惯性力取代浮升力为主导,换热恢复为强制对流换热,强化了换热;浮升力无量纲因子Bo*可以有效预测自然对流对换热的影响程度,强制对流换热向混合对流换热转变的Bo*数临界值为3.69×10^(-8)。The numerical simulation on convective heat transfer in the vertical upward flow of methane under the supercritical pressure was carried out by the RNG k-εturbulence model in combination with the enhanced wall function.The dimensionless force analysis was carried out,then a buoyancy criterion for the low temperature methane has been proposed.The result shows that the increase of the heat flux and the decrease of the mass flux will both lead to abnormal phenomena in heat transfer near the pseudo-critical temperature.When the density ratio increases,the natural convection caused by buoyancy increases,which leads to the mixed convection heat transfer and deterioration.With the decrease of the density ratio,the inertial force caused by the decrease of viscosity becomes dominant,and the heat transfer returns to the forced convection,which strengthens the heat transfer.The dimensionless factor Bo*of buoyancy can effectively predict the influence of the natural convection on the heat transfer,and the critical value of Bo*number for the transition from the forced convection heat transfer to the mixed convection heat transfer was found to be 3.69×10^(-8).

关 键 词：超临界压力 甲烷 竖直圆管 混合对流 浮升力 

分 类 号：TK124[动力工程及工程热物理—工程热物理]