Abstract: In order to explore the relationship between the relative flow direction and the mixing performance of the jet and the cross-flow of the central multi-strand jet reactor, the concept of three-dimensional jet angle represented by normal angle α and rotation angle θ was proposed and defined, and the mixing performance of various jet angles in space was simulated by fluent multiphase flow model. Firstly, the conditions of the numerical simulation were determined by the combination of numerical simulation and experiment, so as to ensure the accuracy of the simulation and conform to the regularity of the experiment. The results showed that under the mixture model, the concentration field obtained by the simulation was close to the distribution law obtained by the experiment, so the simulation can better reflect the internal concentration distribution of the reactor. Secondly, the reactor under the research angle was analyzed through the simulation, the qualitative analysis was carried out through the concentration contour of each section, and the quantitative analysis of the separation intensity of the cross-section, and the change law of the angle on the swirl intensity in the reactor were studied. It was found that θ=67.5° is the ideal rotation angle, and the reactors showed a good mixing effect at this angle. With the increase of θ, the pitch of the fluid trajectory at the mixing development section decreased gradually, and the swirling intensity increased gradually. The pressure drop of the inlet and outlet sections increased with the increase of the rotation angle, and the increase amplitude increased with the increase of the normal angle. At α=30°, θ=90° the slope of the separation intensity decreased the most, indicating that it can make the separation strength reach 0.05. With the increase of θ, the pitch of the mixed development section decreased and the swirling effect increased. The distance of the jet hitting the wall was proportional to the α and inversely proportional to θ.

Key words: three-dimensional jet angle, separation strength, jet flow, swirling flow, impact depth

摘要： 为了探究中心多股射流反应器射流与横流相对流动方向与混合性能之间的关系，提出了以法向角α和旋转角θ表征的三维射流角度概念，采用Fluent多相流模型对空间多种射流角度下的混合性能进行了模拟研究。结果表明，在各个角度下，分离强度随着轴向距离增加而减小，且在第六列射流管之前分离强度下降幅度最大；θ=67.5°是较为理想的旋转角，在此角度下各反应器均呈现较好的混合效果；进出口截面的压降随着旋转角增大而提高，且上升幅度随着α增大而升高；θ=90°时分离强度下降斜率最大，说明其能够在较短距离使分离强度达到0.05；随θ增大，混合发展段螺距减小，旋流作用增强；射流冲击壁面的距离与α成正比，与θ成反比。

关键词: 三维射流角度, 分离强度, 射流, 旋流, 冲击深度