论文部分内容阅读
本文用数值模拟的方法研究了螺旋纽带在圆管中引发的涡流形成过程与机理,分别用RNGκ-ε和RSM模型模拟计算,并与相关文献的实验结果进行对比,用更准确的RSM模型进行后续研究。在螺旋纽带中,由于边界层分离,先出现两个涡,根据角动量守恒,这两个涡的旋向与纽带旋向相反,在主流切向速度的作用下,这两个涡逐渐衰减,在衰减过程中,同样由于边界层分离,形成与纽带旋向相同的两个涡,这四个涡会暂时共存,之后逐渐减弱消失,随着流动的发展,由于流线弯曲不稳定,出现旋向与纽带相同的两个涡,并一直维持此涡结构。螺旋纽带中的二次流动是在壁面切应力,科氏力和离心力综合作用下产生的。
In this paper, the formation process and mechanism of spiral vortex-induced eddy currents in a circular tube were studied by numerical simulation. The simulation was carried out by using RNG κ-ε and RSM models, respectively, and compared with the experimental results of the relevant literature. The more accurate RSM model follow up research. Due to the separation of the boundary layer, two vortices appear first in the spiral bond. According to the conservation of angular momentum, the vortices of these two vortices are opposite in direction of rotation to the opposite direction. Under the action of the mainstream tangential velocity, the two vortices gradually decay, During the process of decay, the same two vortices are formed due to the separation of the boundary layer, and the four vortices coexist for a while and then gradually disappear. As the flow develops, due to the unsteady flow curve, To the same two vortices, and maintain the vortex structure. The secondary flow in the spiral bonds is generated by the combination of wall shear stress, Coriolis force and centrifugal force.