Abstract: Static mixers, which do not require external energy sources, are characterized by their compact design and ease of integration into systems, making them highly valued in the food processing industry. The introduction of vortices can significantly enhance the mixing efficiency of mixers, leading to improved reaction rates and overall effectiveness. Currently, most vortex static mixers achieve high-efficiency mixing by generating vortices through their internal structures, which must withstand the impact of flow and thus carry a risk of damage. Vortex tubes, characterized by their simple structure and strong vortex properties, have yet to be studied for their effectiveness in mixing. Based on this, this work investigates a vortex static mixer, employs numerical simulation methods to study its flow and mixing characteristics, focusing on the effects of inlet velocity and structural parameters such as the chamber aspect ratio (D/H) and the axial diameter ratio (D/Da). The results show that the internal flow is primarily dominated by vortices, accompanied by significant secondary flows, including secondary vortex circulation flow zone, shortcut flow zone, and eccentric vortex zone. Increasing the inlet velocity enhances the internal vortex flow and weakens the secondary flow, significantly reduces the intensity of separation at the outlet. When the inlet velocity reaches 0.223 m/s, complete mixing can be achieved at the chamber outlet. Reducing D/H or increasing D/Da can enhance the internal vortex. The mixing performance improves as the D/H decreases. Specifically, when the D/H is reduced from 6 to 4, the intensity of separation at vortex chamber outlet decreases from 4.03×10-3 to 5.23×10-4.

Key words: mixing, static mixer, vortex tube, CFD, vortex, secondary flow

摘要： 静态混合器无须外部能源、结构紧凑、集成便利，在食品加工行业中具有重要地位。其中涡流的引入能够显著提升其混合效率，提高反应效率及效果。目前主流涡流静态混合器通过内部结构产生涡流以达成高效混合，其结构需承受流动冲击，有损坏风险。本工作研究了一种涡流静态混合器，并通过数值模拟方法研究其流动与混合特性，考察了入口流速及结构参数，包括腔室长径比(D/H)和轴向管径比(D/Da)的影响。结果表明，混合器内部以涡流为主，伴有显著二次流，包括二次涡循环流区、短路流区以及偏心涡区。提高入口流速增强了内部涡流流动，减弱了二次流，出口分离强度显著减小。当流速达0.223 m/s，可于腔室出口达到完全混合。减小D/H或增加D/Da可强化内部涡流流动，混合效果随D/H减小而增强，随D/H由6减小至4，涡流腔出口分离强度由4.03×10-3减少至5.23×10-4。

关键词: 混合, 静态混合器, 涡流管, 计算流体力学, 涡流, 二次流