添加剂湍流减阻流动的传热特性数值计算

Numerical simulation on heat transfer characteristics for turbulent drag-reducing flow with additives

采用雷诺应力模型和Cross粘度方程,对二维轴对称圆管内湍流流动的聚丙烯酰胺稀溶液(PAM)的流场和温度场进行了数值模拟.在数值计算结果的基础上,系统研究了流速对减阻流体的减阻性能和传热特性的影响.结果表明,减阻流体的减阻率和传热降低率随流速的增大逐渐增大到渐进值,而且传热降低率恒大于减阻率.减阻流体柯尔本(Colburn)因子与摩擦系数的对比结果表明柯尔本比拟,特别是在较低流动雷诺数下有较大偏差.

The reynolds stress model and the Cross viscosity equation have been adopted to simulate the turbulent flow and temperature fields of the dilute polyacrylamide （PALM） solution in a two-dimensional axisymmetric circular tube. The effect of flow velocity on drag reduction and heat transfer performance of drag-reducing fluid have been investigated systematically. The results indicate that the drag reduction （DR） and heat transfer reduction （HTR） of drag-reducing fluid increase with increasing flow velocity and approach the asymptotes, and HTR is greater than DR all the time. The comparison between Colburn factor and friction coefficient shows that Colbum analogy is not so much applicable to the drag-reducing fluid, especially for the low bulk flow Reynolds number conditions.