A Study on the Nonmetallic Inclusion Motions in a Swirling Flow Submerged Entry Nozzle in a New Cylindrical Tundish Design
A Study on the Nonmetallic Inclusion Motions in a Swirling Flow Submerged Entry Nozzle in a New Cylindrical Tundish Design
复制标题
新型圆柱形中间包设计中旋流浸入式水口中非金属夹杂物运动的研究
DOI：
10.1007/s11663-017-1162-y
复制
发表时间：
2018-04-01
影响因子：
3
通讯作者：
Jonsson, Par Goran
中科院分区：
文献类型：
--
作者：
Ni, Peiyuan;Ersson, Mikael;Jonsson, Par Goran
采用拉格朗日粒子跟踪方法，研究了新型中间包式浸没式喷嘴内不同大小和形状的非金属夹杂物。结果表明：由于中间包顶部区域存在较强的旋转钢流，当前圆柱形中间包中的夹杂物难以在该区域残留；0.7 m/s的高旋转流为SEN内形成强大的旋流提供了所需的动量。结果表明，大于40 μ m的包裹体在SEN壁上的沉积程度比较小的包裹体要小。原因是这些大的夹杂物的分离值大于1。因此，旋涡流导致这些大尺寸的包裹体向SEN中心移动。对于非球形夹杂物，与球形夹杂物相比，大尺寸夹杂物沉积在SEN壁上的程度更大。更具体地说，沉积包裹体数的差异在27%左右。总的来说，旋流包含三个区域，即各向同性的核心区、各向异性的湍流区和近壁区。因此，在这种复杂流动中跟踪夹杂物运动时，应考虑各向异性湍流波动。此外，在SEN入口区域发现了许多包裹体沉积。绘制的速度分布表明，进口气流非常混乱。该区域湍流动能较高，约为0.08 m2/s2，并存在再循环流动。这些流动特性是有害的，因为它们增加了包裹体向壁面的输运。因此，未来应该开发一种新的SEN进口设计，旨在改变进口流量，以减少夹杂物沉积。
Different sizes and shapes of nonmetallic inclusions in a swirling flow submerged entry nozzle (SEN) placed in a new tundish design were investigated by using a Lagrangian particle tracking scheme. The results show that inclusions in the current cylindrical tundish have difficulties remaining in the top tundish region, since a strong rotational steel flow exists in this region. This high rotational flow of 0.7 m/s provides the required momentum for the formation of a strong swirling flow inside the SEN. The results show that inclusions larger than 40µm were found to deposit to a smaller extent on the SEN wall compared to smaller inclusions. The reason is that these large inclusions have Separation number values larger than 1. Thus, the swirling flow causes these large size inclusions to move toward the SEN center. For the nonspherical inclusions, large size inclusions were found to be deposited on the SEN wall to a larger extent, compared to spherical inclusions. More specifically, the difference of the deposited inclusion number is around 27 pct. Overall, it was found that the swirling flow contains three regions, namely, the isotropic core region, the anisotropic turbulence region and the near-wall region. Therefore, anisotropic turbulent fluctuations should be taken into account when the inclusion motion was tracked in this complex flow. In addition, many inclusions were found to deposit at the SEN inlet region. The plotted velocity distribution shows that the inlet flow is very chaotic. A high turbulent kinetic energy value of around 0.08 m2/s2exists in this region, and a recirculating flow was also found here. These flow characteristics are harmful since they increase the inclusion transport toward the wall. Therefore, a new design of the SEN inlet should be developed in the future, with the aim to modify the inlet flow so that the inclusion deposition is reduced.