A high-throughput (105.5 g/h) passive four-stage asymmetric oscillating feedback microreactor using chaotic mixing mechanism was developed to prepare aggregated Barium sulfate (BaSO₄) particles of high primary nanoparticle size uniformity. Three-dimensional unsteady simulations showed that chaotic mixing could be induced by three unique secondary flows (i.e., vortex, recirculation, and oscillation), and the fluid oscillation mechanism was examined in detail. Simulations and Villermaux–Dushman experiments indicate that almost complete mixing down to molecular level can be achieved and the prepared BaSO₄ nanoparticles were with narrow primary particle size distribution (PSD) having geometric standard deviation, σ_g, less than 1.43 when the total volumetric flow rate Q_total was larger than 10 ml/min. By selecting Q_total and reactant concentrations, average primary particle size can be controlled from 23 to 109 nm as determined by microscopy. An average size of 26 nm with narrow primary PSD (σ_g = 1.22) could be achieved at Q_total of 160 ml/min.

中文翻译：

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用于制备均匀聚集的硫酸钡纳米粒子的高通量混沌对流微反应器

开发了一种采用混沌混合机制的高通量（105.5 g/h）无源四级非对称振荡反馈微反应器，以制备具有高初级纳米粒径均匀性的聚集硫酸钡（BaSO ₄）颗粒。三维非定常模拟表明，混沌混合可以由三种独特的二次流（即涡流、再循环和振荡）引起，并详细研究了流体的振荡机制。模拟和 Villermaux-Dushman 实验表明可以实现几乎完全混合到分子水平，并且制备的 BaSO ₄纳米颗粒具有窄的初级粒径分布 (PSD)，具有几何标准偏差，σ _g，当总体积流量Q _total大于 10 ml/min 时，小于 1.43。通过选择Q_总浓度和反应物浓度，可以将平均初级粒径控制在 23 到 109 nm 之间，如显微镜所确定的那样。在Q_总量为 160 ml/min 时，可以实现26 nm 的平均尺寸和窄的初级 PSD ( σ _{g = 1.22)。}