摘要
采用计算流体力学方法,在恒壁温加热条件下对幂律流体(黄原胶溶液)在螺旋管内的流动换热情况进行模拟。在湍流流态下,模拟分析流体雷诺数、管壁相对粗糙度、管子截面形状、螺旋管曲率、螺旋管螺距等对螺旋管对流传热性能(以努塞尔数表征)的影响,分析螺旋管内流体温度场分布。雷诺数、相对粗糙度的影响:管壁相对粗糙度一定时,努塞尔数随雷诺数的增大而增大,对流传热能力得到加强。雷诺数一定时,管壁相对粗糙度越大,努塞尔数越大,尤其在高雷诺数条件下。截面形状的影响:相对粗糙度、雷诺数相同条件下,管子为方管时的努塞尔数小于圆管。螺旋管曲率的影响:在管子内半径一定时,相同壁面粗糙度下,螺旋管曲率越大,努塞尔数越大。在黄原胶溶液雷诺数一定时,与管壁相对粗糙度相比,螺旋管曲率对努塞尔数的影响更显著。螺旋管螺距的影响:在螺旋管螺旋半径一定时,相同壁面相对粗糙度下,螺距越大,努塞尔数越大。在黄原胶溶液雷诺数一定时,与螺距相比,螺旋管曲率对努塞尔数的影响更显著。沿螺旋管黄原胶溶液温度升高,近管子壁面的溶液温度高于管子中心,低温区域远离螺旋管中心。
The flow and heat transfer of power-law fluid( xanthan gum solution) in a spiral tube are simulated by computational fluid dynamics( CFD) under constant wall temperature heating. In turbulent flow,the effects of Reynolds number of fluid,relative roughness of tube wall,cross-section shape of tube,curvature and pitch of spiral tube on the convective heat transfer performance of spiral tube( characterized by Nusselt number) are simulated and analyzed. The fluid temperature field distribution in the spiral tube is analyzed. The influence of Reynolds number and relative roughness: when the relative roughness of the tube wall is constant,the Nusselt number increases with the increase of Reynolds number,and the convective heat transfer ability is enhanced. When the Reynolds number is constant,the greater the relative roughness of the tube wall is,the greater the Nusselt number is,especially under the condition of high Reynolds number.The influence of cross-section shape: under the condition of the same relative roughness and Reynolds number,the Nusselt number of square tube is smaller than that of circular tube. The influence of the curvature of the spiral tube: when the inner radius of the tube is constant,the larger the curvature of the spiral tube,the greater the Nusselt number under the same wall roughness. When the Reynolds number of xanthan gum solution is constant,the curvature of spiral tube has more significant effect on Nusselt number than the relative roughness of tube wall. The influence of the pitch of the spiral tube: when the spiral radius of the spiral tube is constant,the larger the pitch,the greater the Nusselt number under the same relative roughness of the wall. When the Reynolds number of xanthan gum solution is constant,the curvature of spiral tube has more significant effect on Nusselt number than the pitch. The temperature of xanthan gum solution increases along the spiral tube,and the solution temperature near the tube wall is higher than that at the tube center,and the low temperature area is far away from the spiral tube center.
作者
张浩
包晓琳
康艳蓓
ZHANG Hao;BAO Xiaolin;KANG Yanbei
出处
《煤气与热力》
2020年第5期1-4,12,J0041,共6页
Gas & Heat
关键词
螺旋管
幂律流体
努塞尔数
传热
spiral tube
power-law fluid
Nusselt number
heat transfer
