外圆柱沟槽对环隙内波动涡流的影响

采用CFD数值计算方法对同心圆柱环隙内的波动涡流进行了数值模拟,根据PIV试验结果验证了数值计算方法的可靠性.重点研究了光壁模型和沟槽数量为9的2个模型环隙内的流场分布以及波动涡流的波动特性,对比分析了2种模型周向的流场分布,计算了泰勒涡的轴向尺寸及其轴向振幅,通过对比2种模型在R-Z平面上的径向速度分布,讨论了沟槽对环隙内流体的外射流作用的影响,分析了沟槽区域的流动特征以及出现的二次流现象.研究结果表明:沟槽的存在显著改变了环隙内的流场分布以及波动涡流的波动特性,沟槽区域形成的旋涡流动促进了沟槽内流体与环隙内流体的相互作用,加剧了环隙内的流动不稳定性.

Effect of exterior cylinder slit wall on wavy vortex flow in gap of concentric cylinders

Numerical simulations were implemented by using CFD to investigate the wavy vortex flow inside concentric cylindrical annulus. The reliability of numerical method was verified by the experimental results of PIV. The research focused on the distribution of flow field and the fluctuation characteristics of wavy vortex flow in the plain and slit wall models. By studying the velocity field of the circumferential plane for two different models, the size of Taylor vortex and the fluctuation amplitude in axial direction of wavy vortex were analyzed. By comparing the radial velocity distribution in R-Z plane in two different models, the influence of slit wall on jet outflow effect was discussed. Meanwhile, the flow characteristic and the secondary flow phenomena in the slit regions were discussed. The results show that: the existence of slit wall changed the distribution of flow field inside the annulus and the fluctuation characteristics in axial direction of wavy vortex. An obvious secondary flow phenomena in the slit regions promoted the fluid mixing and diffusion between the slit region and the annulus, intensified the instability of wavy vortex flow inside the annulus.