基于圆管内肋迎流面结构设计的传热性能研究

Research on heat transfer performance based on structural design of upstream surface of inner rib in circular tube

相较于光滑圆管,内肋管对管内流体流动状态影响较大。通过改变肋片迎流面结构,会对流体产生不同程度的导流效果。传统对于肋片结构方面的研究多是一些规则化的图形,其导流角往往是一致的。本文采用数值模拟的方法研究了环形内肋迎流面的结构对圆管内流体流动特性、传热特性及综合性能的影响。对内肋迎流面以不同程度的凹凸结构建立5种圆管模型,分析比较5种流体模型对流体的影响并探讨其规律。结果表明:圆管整体换热和综合性能与迎流面凹凸程度具有强烈的相关性;内肋迎流面凹陷对换热管换热有强化效果,内肋迎流面凸出则会削弱换热管换热;同时,凹面管的阻力系数比凸面管的阻力系数有较大幅度的增加;迎流面凸面结构综合性能略高于迎流面凹面结构。

Compared with smooth tube,inner rib tube can greatly affect the fluid flow state in the tube.By changing the structure of upstream surface of the fin,different degrees of flow diversion effect will be produced.Conventional researches on fin structure are mostly regular figures,and the diversion angle is always consistent.In this paper,the effects of the structure of the upstream surface of the inner rib on the flow characteristics,heat transfer characteristics and comprehensive performance of the fluid in a circular tube are studied by numerical simulation.Five kinds of tube models are established with different concave convex structures on the upstream surface of the inner rib,and the effects of the five fluid models on the fluid are analyzed and compared,and their laws are discussed.The results show that,there is a strong correlation between the overall heat transfer performance and the convexity of the upstream surface.The sunken of the upstream surface of the inner rib can enhance the heat transfer of the heat exchange pipe,and the protruding of the upstream surface of the inner rib will weaken the heat transfer of the heat exchange pipe.At the same time,the resistance coefficient of the concave tube is higher than that of convex tube,and the comprehensive performance of the convex structure is slightly higher than that of the concave structure.