二维球状式扩展翅片自然对流换热的数值研究  

Numerical study on natural convection heat transfer in two-dimensional spherical extended fins

作　　者：黄兴 王哲 吕文兵 廖能 朱天顺 HUANG Xing;WANG Zhe;LYU Wenbing;LIAO Neng;ZHU Tianshun(Air Force Early Warning Academy,Wuhan 430019,China)

机构地区：[1]空军预警学院,武汉430019

出　　处：《空天预警研究学报》2025年第2期141-146,共6页JOURNAL OF AIR & SPACE EARLY WARNING RESEARCH

基　　金：湖北省教育厅科学研究计划指导项目(B2023420)。

摘　　要：针对工业领域中球状式扩展翅片圆管结构自然对流换热理论研究匮乏的问题,本文基于Bejan理论建立了二维层流自然对流换热数值模型,采用定热流边界条件与制冷剂R134a,对瑞利数(Ra)在10^(3)≤Ra≤10^(6)范围内的球状式扩展翅片开展了深入的数值研究.研究结果表明:较大的瑞利数导致对流效应和卷吸效应增强,进而使得温度边界层和速度边界层厚度减小,并且局部最大无量纲温度减小;位于中心线的上下端是两个滞止点,相应的摩擦系数为0;边界层的发展一直处于顺压力梯度,因受几何曲率影响,压力系数并未一直增大.最后建立了平均努塞尔数与瑞利数之间的经验关联式.In response to the scarcity of theoretical research on natural convection heat transfer of spherical extended fin tubular structures in the industrial field,this paper establishes a two-dimensional laminar natural convection heat transfer numerical model based on Bejan Theory,and then employs the constant heat flux boundary condition and the refrigerant R134a to make an in-depth numerical study on spherical extended fins of Rayleigh number in the range of 103£Ra£106.The study findings go as follows:The larger Rayleigh number leads to the enhancement of convective effect and entrainment effect.As a result,the thickness of temperature boundary layer and velocity boundary layer decreases,and the local maximum dimensionless temperature also decreases.At the upper and lower ends of the centerline are two stagnation points,with a corresponding friction coefficient of zero.The development of the boundary layer is consistently under a favorable pressure gradient,and the pressure coefficient does not always increase due to the geometric curvature effect.Finally,the empirical correlation between the mean Nussel number and Rayleigh number is established.

关 键 词：自然对流 球状式扩展翅片 定热流边界条件 换热关联式 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TP391.9[动力工程及工程热物理—热能工程]