Nanoprecipitation in Turbulent Liquid-Phase Vortex Reactors: A Fundamental Investigation of Scale Up Using Experimentally Validated CFD Models

0932978Olsen从疏水有机化合物中通过经济、可扩展的工艺生产尺寸均匀的纳米颗粒是非常具有挑战性的。生产尺寸精确控制的功能纳米颗粒的最先进工艺之一是闪光纳米沉淀，它需要两个或两个以上的流非常快速地混合，以产生均匀的过饱和。目前，闪蒸纳米沉淀法仅在生产规模较小的微型反应器中得到验证。这一限制只适用于特定的应用，例如生产高价值的药剂。其他应用，如用于杀虫剂和化妆品的纳米粒子的制造，将需要更大的生产周期，这使得微型反应堆在经济上是不现实的。为此，本研究项目将采用实验和模拟相结合的方法，研究从闪速纳米沉淀到能够产生大量功能纳米粒子的大规模反应器的流体动力学和标量传输过程。要从根本上理解快速沉淀，需要详细了解宏观、中观和微观混合在过饱和度发展中的作用，闪光纳米沉淀所需工艺条件的可扩展性(例如毫秒级微混合)是一个悬而未决的问题，将在这里讨论。为了回答这个问题，我们将利用非侵入式光学测量技术对大尺度多进旋涡混合器(MIVM)反应器内的湍流反应混合进行研究，并将这些实验结果用于建立和验证混合和反应过程的计算流体动力学(CFD)模型。实验技术将包括时间相关(高速)立体粒子图像测速(SPIV)、被动标量和反应性平面激光诱导荧光(PLIF)以及同步PIV/PLIF。CFD模型将基于大涡模拟(LES)和使用直接求积矩方法(DQMOM)求解的传输概率密度函数(PDF)模型。一旦开发和验证，这些CFD模型可被化工过程工业用作优化反应器设计和操作参数的工程工具，以在工厂规模的MIVM反应堆中生产定制的功能纳米颗粒。智力优势：发展湍流反应流的计算模型，特别是在涡流反应器等复杂的旋转几何形状中，是一项重要的技术和智力挑战。例如，湍流反应流CFD模型中化学源项的亚网格尺度闭合对于复杂的液相反应流没有得到充分的验证，这是由于缺乏关于明确定义的反应器几何结构中的局部速度场和浓度场的详细实验数据。更广泛的影响：闪光纳米沉淀显示出生产统一尺寸的有机化合物功能纳米颗粒的前景。然而，这一过程只在能够生产非常小的生产批次的微型反应堆中得到演示。将闪光纳米沉淀法扩大到大规模的MIVM反应器可以极大地提高这一工艺的商业可行性，以制造更广泛的有价值的最终产品。该项目还将培训学生使用最先进的工程工具来扩大规模和设计化学反应堆。

0932978OlsenThe production of uniform-sized nanoparticles from hydrophobic organic compounds by an economical, scalable process is very challenging. One of the most advanced processes to produce functional nanoparticles of precisely controlled size is Flash NanoPrecipitation, which requires very fast mixing of two or more streams to create uniform supersaturation. Presently, Flash NanoPrecipitation has only been demonstrated in microscale reactors with small production runs. This limitation is only suitable for selected applications, such as the production of high-value pharmaceutical agents. Other applications, such as the manufacturing of nanoparticles used in pesticides and cosmetics, will require much larger production runs, making microscale reactors economically unrealistic. For this reason the fluid dynamics and scalar transport processes associated with scale up Flash NanoPrecipitation to macroscale reactors capable of generating large quantities of functional nanoparticles will be investigated using a combined experimental and modeling approach in this research project. A fundamental understanding of rapid precipitation requires a detailed knowledge of the roles of macro, meso- and micromixing on the development of supersaturation, and the scalability of the processing conditions needed for Flash NanoPrecipitation (e.g. millisecond micromixing) is an open question that will be addressed here. To answer this question, turbulent reactive mixing in a macroscale multi-inlet vortex mixer (MIVM) reactor will be studied using non-intrusive optically based measurement techniques, and the results from these experiments will be used to develop and validate computational fluid dynamics (CFD) models of the mixing and reaction processes. The experimental techniques will include time-correlated (high-speed) stereo particle image velocimetry (SPIV), passive scalar and reactive planar laser induced fluorescence (PLIF), and simultaneous PIV/PLIF. The CFD models will be based on large eddy simulations (LES) and transported probability density function (PDF) models solved using the direct quadrature method of moments (DQMOM). Once developed and validated, these CFD models can be used by the chemical process industry as engineering tools for optimizing reactor design and operating parameters to produce customized functional nanoparticles in plant-scale MIVM reactors. Intellectual Merit: The development of computational models of turbulent reacting flows, especially in complex swirling geometries such as in a vortex reactor, is an important technical and intellectual challenge. For example, none of the subgrid scale closures for the chemical source term in CFD models of turbulent reacting flows have been fully validated for complex liquid-phase reacting flows due to a lack of detailed experimental data for the local velocity and concentration fields in well-defined reactor geometries. Broader Impact: Flash NanoPrecipitation shows promise for producing uniform-sized functional nanoparticles of organic compounds. However, this process has only been demonstrated in microscale reactors capable of producing only very small production runs. Scaling up the Flash NanoPrecipitation process to a macroscale MIVM reactor could greatly increase the commercial viability of this process for manufacturing a wider range of valuable end products. This project will also train students in state-of-the art engineering tools for scale up and design of chemical reactors.