变径管湍流流动与传热特性数值模拟研究  

Numerical simulation of turbulent flow and heat transfer characteristics of variable diameter tubes

作　　者：石若冉 张浩[1,2] 李茂林 张志 Shi Ruoran;Zhang Hao;Li Maolin;Zhang Zhi(College of Thermal Engineering,Shandong Jianzhu University;Shandong Collaborative Innovation Center of Green Building)

机构地区：[1]山东建筑大学热能工程学院 [2]山东省绿色建筑协同创新中心

出　　处：《区域供热》2022年第6期99-105,共7页District Heating

基　　金：山东省专业学位研究生教学案例库项目(SDYAL20162);山东省研究生优质课程建设项目(SDYKC19117)。

摘　　要：为探究变径圆管的湍流流动和传热特性,利用数值模拟法对具有突缩突扩变径结构的对称二维圆管在约10^(4)~1.2×10^(5)雷诺数范围内的湍流工况进行研究,对其流场、阻力系数、回流区及温度场、努塞尔数的变化进行分析。结果表明:流体流经变径段前后产生了多处涡旋结构,其对下游影响相较上游更大,流动恢复充分发展需要更长的距离;随雷诺数的增加,直管段沿程阻力系数减小,变径结构处局部阻力系数在雷诺数大于79617后便保持稳定,回流区长度随之先增加,后当雷诺数大于99521后长度不再变化;变径段附近流体温度明显升高;平均努塞尔数随雷诺数增加呈现增长趋势。In order to explore the turbulent flow and heat transfer characteristics of the variable diameter circular tube,the numerical simulation method is used to study the turbulent flow conditions of the symmetrical two-dimensional circular tube with the sudden contraction and sudden expansion variable diameter structure in the range of about 10^(4)~1.2×10^(5) Reynolds number,and analyze the changes of its flow field,resistance coefficient,recirculation zone,Nusselt number and temperature field.The results show that multiple vortex structures are generated before and after the fluid flows through the variable diameter section,which has a greater influence on the downstream than upstream,and it means that it takes a longer distance to return to fully developed flow;with the increase of Reynolds number,the resistance coefficient of the straight pipe section shows a downward trend,and the local resistance coefficient of the variable diameter structure remains stable after the Reynolds number is greater than 79617,and the length of the recirculation zone increases at first,and then does not change after Reynolds number is greater than 99521;the fluid temperature near the variable diameter section increases significantly;the average Nusselt number increases with the increase of Reynolds number.

关 键 词：变径 湍流流动 传热 

分 类 号：O357.5[理学—流体力学] TK124[理学—力学]