高速撞击流反应器内流动和微观混合特性的研究

High-speed impinging jets are novel methods to intensify complex and rapid chemical reaction processes where the transfer between reactants is usually insufficient. Based on our previous work, large eddy simulation (LES) method using multi-scale turbulence theory and particle image velocimetry (PIV) technique with high resolution will be utilized to numerically simulate and experimentally investigate the flow characteristics in the high-speed impinging jets reactors (HIJR) with jet velocities ranged from 30 m/s to 100 m/s. The parallel competing reaction system which acts as molecular probe will also be adopted to investigate the micromixing characteristics of HIJR. The effect of the structure type, the geometrical parameter, and the operating condition of HIJRs on the flow and micromixing characteristics will be analyzed and discussed in detail, and the corresponding mathematical models and numerical methods will be established. The results of this project will provide theoretical basis and implementation method for the process intensification in complex and rapid chemical reaction systems, improve the selectivity of the reactions, and promote the development of chemical reaction engineering.

对于传递受限的复杂快速反应体系，高速撞击流是强化这类反应过程的新方法。本项目在已有研究的基础上，采用基于多尺度湍流理论的大涡模拟方法（LES）和高解析度的流场测试技术（PIV）对高速撞击流反应器内（两股来流速度范围：30-100 m/s）的流动结构进行数值模拟和实验研究，并采用"分子探针"平行竞争反应工作体系实验研究高速撞击流反应器内的微观混合特性，分析研究高速撞击流反应器结构型式、几何参数和操作条件对其流动特性和微观混合的作用机理和影响规律，并建立相应的数学模型和数值方法。研究成果可为复杂快速反应体系的过程强化提供理论依据和实施方法，以便从根源上提高反应选择性，促进化学反应工程的发展。

本研究采用大涡模拟方法（LES）和高解析率的粒子图像测速（PIV）技术对高速撞击流反应器内的流动结构进行数值模拟和实验研究，并采用平行竞争反应工作体系实验研究了该反应器内的微观混合性能。结果表明，反应器内撞击区域湍动剧烈，几何参数如入口管径及腔体尺寸和操作条件如入口速度比等对流场结构影响显著，而雷诺数对无因次化流场基本无影响。据此可调控和强化反应器内传递过程。大涡模拟结果与PIV实验吻合良好，证明本研究构建的模型和方法准确，且可替代部分PIV实验。反应器内微观混合时间可控制在微秒级别，远优于传统搅拌反应器。因此，高速撞击流是一种有效的过程强化技术。