底部加热方腔内的相变传热过程及其非线性特性  

Phase Change Heat Transfer Process in a Square Bottom-heated Cavity and the Nonlinearity

作　　者：陈刚 杨茉[1] 张政[1] 胡卓焕[1] CHEN Gang;YANG Mo;ZHANG Zheng;HU Zhuohuan(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093

出　　处：《动力工程学报》2020年第10期815-819,831,共6页Journal of Chinese Society of Power Engineering

基　　金：国家自然科学基金资助项目(51736007)。

摘　　要：利用Fluent软件和焓法模型对方腔内石蜡受热融化的相变传热过程进行数值计算,研究了方腔内温度场和速度场的变化规律,并对比分析了在不同瑞利数Ra下的液相自然对流情况。结果表明:相变传热先以导热为主,随着石蜡液相率的增大,相变传热以对流换热为主;随着斯蒂芬数Ste的增大,石蜡的融化速度加快;当瑞利数Ra较小时,相变传热过程中的速度是稳定的,随着Ra的增大,速度出现周期性振荡,当Ra较大时速度呈混沌无序的振荡状态,说明相变传热具有复杂的非线性特性。Phase change heat transfer process of the paraffin heated and melted in a square cavity was calculated by Fluent software and enthalpy method,so as to study the variation law of temperature field and velocity field in the square cavity,and to comparatively analyze the phase change heat transfer at different numbers of Ra in the case of natural convection of liquid phase.Results show that the phase change heat transfer is mainly in the form of heat conduction at first,and then it turns to the form of natural convection,with the rise of liquid fraction of paraffin;as the number of Ste rises,the melting speed of paraffin increases.When the number of Ra is relatively small,the velocity field keeps stable in the phase change heat transfer process,and with the rise of Ra,the velocity field starts to oscillate periodically,and when the Ra is relatively large,the velocity field oscillates chaotically,indicating complex nonlinear characteristics of the phase change heat transfer process.

关 键 词：方腔 相变材料 自然对流 非对称流动 非线性 

分 类 号：TK229.2[动力工程及工程热物理—动力机械及工程]