单管多旋构件诱导静态混合器内气液两相非稳态流动及混合增强机理研究

The static mixer with multiple spiral flow passages has been proposed as a novel gas-liquid mixing equipment. It has been successfully applied in the industrialized production of dichloroethane by direct chlorination of ethylene and propylene oxide by chlorohydrination in tubular reactor dichloride. During the past years, the static mixers have displayed fantastic performance of mass transfer and mixing intensification in the new processes aforementioned. In order to reveal the instantaneous hydrodynamics characteristics and mixing intensification mechanism in gas-liquid flow, the Time-Resolution PIV and computational fluid dynamics models of gas-liquid flow are employed. Firstly, both the instantaneous evolution characteristics of bubble groups and liquid flow field will be investigated in the different regions, such as in the empty tube region after inlet, flow division and reversal region, flow recombined region and decay region before outlet. The coalescence and collapse behaviors of bubble groups and spatial-temporal distributions of liquid will be evaluated under different velocities, physical properties of mixing medium, structures and sizes of periodic variable cross-section passages, respectively. Secondly, the flow pattern maps of gas-liquid two phase flow will be presented based on the synchronous experiments of instantaneous pressure time series and performance of bubble groups from PIV. And then the online identification will be developed on the basis of the community structure of complex networks. At last, the intensification performances and concentration distributions across the gas-liquid interface will be investigated based on PLIF, mass transfer convection-diffusion equation and Navier-Stokes equations. The advantage of the new mixing segments instead of standard Kenics element will be proposed based on the improvement of mixing efficiency and concentration distribution, which will provide theoretical support for static mixing technology in more widely applications.

单管多旋静态混合器作为新型气液混合设备，在氯醇化管道反应新工艺生产环氧丙烷和乙烯直接氯化制二氯乙烷等工业化生产中表现出卓越的强化传质性能。为了揭示周期性变截面螺旋流道诱导气液两相非线性瞬态动力学特性及混合增强机理，首先，利用多相流流体力学方法和高分辨率粒子图像测速仪相结合对静态混合器内进口空管段、过渡分流段、移位汇合段、出口空管尾流段内气泡群瞬态演变行为进行分析，考察气液流速、液体物性、多旋流道结构和尺寸等对气泡聚并、破裂过程及周围液相流场时空分布的影响；其次，基于瞬态压力波动特征和气泡形态图像建立气液两相流型图，并根据其复杂网络社团结构进行流型在线识别；最后，以Navier-Stokes方程和对流-扩散方程为基础，结合PLIF实验，对其开展气液界面浓度分布特性和混合机理的研究，定量分析多旋混合元件较Kenics改善混合器内的浓度分布和强化混合效果状况，为其工业化进一步推广提供理论支持。

单管多旋静态混合器作为新型气液混合设备，在氯醇化管道反应新工艺生产环氧丙烷和乙烯直接氯化制二氯乙烷等工业化生产中表现出卓越的强化传质性能。研究分散相体积分数为零时-单相水为工质各类混合结构参数下单管多旋静态混合器内的微观流体力学特性，分析旋流静态混合器内进口空管段、过渡分流段、移位汇合段和出口空管衰变段内的流体涡场结构和时间序列符号复杂度结构；采用脉冲示踪法和Particle Tracking方法相结合研究单管多旋静态混合器内流体混合运移规律和停留时间分布特性。改变旋流式静态混合器内部不同叶片的排列方式，研究不同结构静态混合器内高粘流体流场的混沌混合特性，探寻静态混合器内流体流动速度场与压力场的协同程度。静态混合器内部的混合元件的结构设计及结构优化对其内部流场和传热特性的影响也受越来越多的关注，研究Q型静态混合器内混合元件的结构设计及结构参数对其内部传热特性的影响；分析Modified扭带上孔的结构参数和扭带交错角对传热性能的影响及其结构优化，基于场协同理论对速度场与温度场之间的协同程度进行分析。进一步分析Q型和Modified型混合元件较标准Kenics改善混合器内的传热分布和强化混合效果状况，为其工业化进一步推广提供理论支持。采用数值模拟计算分析气液流速、液体物性、多螺旋通道结构和尺寸等对旋流静态混合器中不同流动区域的漩涡结构、湍动耗散情况及气含率的影响。