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    声共振对心形微反应器微观混合性能的强化

    Effects of acoustic resonance intensification on micromixing performance in a heart-shaped microreactor

    • 摘要: 针对微通道内层流主导导致混合受限的问题,本文引入低频高强声共振作为主动式外部激励,以强化心形微反应器内的微观混合性能。采用Villermaux-Dushman平行竞争反应体系,系统考察了振动强度与入口流量对混合效果的影响,并通过离集指数(XS)、微观混合时间(tm)及达姆科勒数(Da)进行定量表征。结果表明:声共振诱导的瞬态惯性力与二次流打破了层流稳定性,显著促进了全流场范围内的混沌对流与组分掺混。与无振动工况相比,施加声共振后XS显著降低了11.3%~84.5%,tm由1.94×10−4~7.27×10−4 s大幅缩短至5.50×10−5~1.08×10−4 s。在所有强化工况下,Da均小于1(最低至0.12),表明系统已跨入反应动力学控制区,成功解除了微尺度下的混合瓶颈。该技术有效改善了混合与反应的时间尺度匹配,为微反应器的过程强化设计及难混合体系的工业应用提供了全新的策略与数据支撑。

       

      Abstract: To overcome the inherent mixing limitations dominated by laminar flow in microchannels, low-frequency and high-intensity acoustic resonance was introduced as an active external excitation to intensify the micromixing performance within a heart-shaped microreactor. Experimental investigations were systematically conducted using the Villermaux-Dushman parallel competitive reaction system. The micromixing efficiency was quantitatively characterized using the segregation index (XS), micromixing time (tm), and Damköhler number (Da). The results demonstrate that the transient inertial forces and secondary flows induced by acoustic resonance effectively disrupt laminar stability, significantly enhancing chaotic advection and species blending across the entire flow field. Compared to non-vibrated conditions, the application of acoustic resonance decreased XS by 11.3% to 84.5% and drastically reduced tm from 1.94×10−4–7.27×10−4 s to 5.50×10−5–1.08×10−4 s. Under all intensified operating conditions, Da remained below 1 (reaching a minimum of 0.12), indicating that the system transitions into a reaction-controlled regime, thereby eliminating the micromixing bottleneck. This acoustic resonance strategy efficiently matches the time scales of mixing and chemical reactions, providing a novel approach and robust data support for the process intensification and industrial application of microreactors.

       

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