应用热阻分析缩放管强化传热机理  

Mechanism of heat transfer enhancement for converging-diverging tubes and thermal resistance distribution

作　　者：黄维军[1] 邓先和[1] 周水洪[1] 

机构地区：[1]华南理工大学化工与能源学院教育部传热强化与过程节能重点实验室

出　　处：《化学工程》2006年第9期13-16,共4页Chemical Engineering(China)

基　　金：国家重点基础研究发展规划项目(G2000026301)

摘　　要：应用分析求解和数值模拟方法对光滑圆管与缩放管内的湍流对流传热的热阻分布进行了计算,计算结果表明,光滑圆管的热阻主要位于粘性底层,缩放管通过壁面缩放,减小了粘性底层的热阻,湍流区成为热阻分布主要区域。在流动粘性底层,缩放管的热阻降低归功于该层厚度的降低,在流动粘性底层以外的传热粘性底层,则是边界层厚度的降低、速度矢量与温度梯度的协同影响。随Re数增大,圆管与缩放管各层热阻均减小,流动粘性底层以外的传热粘性底层的降幅最大。The thermal resistance distribution was calculated by means of analytical solution and numerical simulation for smooth tubes and converging-diverging tubes respectively. The results reveal that major thermal resistance is in viscous sublayer in smooth tubes. In converging-diverging tubes the thermal resistance is mainly in central turbulent core because converging-diverging tubes successfully reduce the thermal resistance in viscous sublayer by enlarging and contracting the flow cross section. The decrease of thermal resistance in flow viscous sublayer owns to thinning the thickness of viscous sublayer, while the decrease of the thermal resistance in thermal viscous sublayer is due to the effects of synergy of velocity and temperature gradient. Thermal resistance in every region is decreasing with the increase of Re number both in smooth and converging-diverging tubes, especially in thermal viscous sublayer, thermal resistance falls greatlv.

关 键 词：热阻 分析求解 数值模拟 缩放管 传热粘性底层 流动过渡区 场协同 温度梯度 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TQ051.5[动力工程及工程热物理—热能工程]