内置短螺旋扭带管内螺旋涡流数值模拟研究

Numerical Simulations of Swirling Flows in a Circular Pipe with Short Twisted Tape Inserts

为了考察螺旋扭带诱发的螺旋流加强传质及传热的动力学机理,以水为介质,利用RSM湍流模型对水平圆管中由短螺旋扭带引发的螺旋单相流进行了数值模拟,从螺旋涡的角度考察其流动特性。结果发现,二次螺旋涡首先在扭带吸力面形成,与未受螺旋涡影响的流场区域相比,由于二次螺旋涡的存在,使压力梯度增加、轴向速度减小、近壁处切向速度值增大1倍,径向速度拥有与切向及轴向速度相同的数量级;多段扭带可减缓旋流强度衰减,但压力损失有所增加。将计算得到的切向速度变化规律与相关的实验结果进行了对比,发现模拟与实验有相同的规律,为管道螺旋流的工业应用提供了理论参考。

In order to investigate the dynamics mechanism of enhancing mass transfer and heat transfer by swirling flows with twisted tape inserts,numerical simulations were used to study the characteristics of the single-phase swirling flow induced by short twisted tapes in a circular pipe with water using Reynolds Stress Model（RSM）.The results showed that,the secondary helical vortices formed firstly in the section side,and the existence of the secondary helical vortices made the radial pressure gradient increased,the axial velocities reduced,the tangential velocities near the wall increased 1times,the radial velocities had the same order of magnitude as the tangential and axial velocities compared with the unaffected flow field;furthermore,lengthened twisted tapes made the swirl intensity decay rate decreased but the pressure loss increased.The comparison between the calculated tangential velocity profiles and the experimental results in the relevant literature showed the same variation pattern.