流速比对管内中心多孔射流与旋流混合的影响

Effect of flow velocity ratio on mixing of swirling flow coupled with central multi-jets in a pipe

提出了一种具有中心多孔射流的旋流式静态混合装置,为了探究流速比R对其混合性能的影响规律,采用Fluent多相流模型对湍流状态下液液两相的浓度分布进行研究。结果表明:在各流速比(R=12—38)下,分离强度及其变化速度均随着轴向距离的增大而减小;在混合器同一横截面内分离强度随着流速比的增大而降低,且降低的幅度亦相应减小;经过4个混合单元后,流体已基本达到完全混合,混合效果随流速比的增加而提高,但相差程度较小(≤0.35%);R=33时是较为理想的工程参数,之后增大流速比对混合效果的影响很小;分离强度在前2个混合单元下降迅速,而在后2个混合单元下降缓慢,说明流体在达到一定混合效果后,后面的混合单元主要起维持混合作用。

A swirling static mixing device with central multi-jets was proposed.To explore the influence of velocity ratio R on its mixing,the concentration distribution of liquid-liquid two-phase flow in turbulent state was studied by using Fluent multiphase flow model.The results show that under the flow velocity ratios studied(R=12-38),the separation strength and its change velocity decrease with the increase of axial distance;in the same cross section of the mixer,the separation strength decreases with the increase of flow rate ratio,and the decreasing range also decreases accordingly;the mixing effect of the two fluids after passing through four mixing units increases with the increase of flow velocity ratio,but the difference is very small(≤0.35%),indicating that they have basically reached complete mixing;R=33 is an ideal engineering parameter,and then increasing the flow rate ratio has little effect on the mixing effect;the separation strength decreases rapidly in the first mixing unit,and decreases slowly in the latter two mixing units.After the fluid achieves a certain mixing effect,the latter two mixing units mainly play a maintenance role.