高气速鼓泡塔中气泡群动力学测量、相间作用力模型和反应器模拟

Lack of reliable research tools leads to the current situation that there exists a gap between research conducted so far and the industrial needs for designing and engineering production-scale bubble columns. It is difficult to design and amplify the bubble column reactor accurately. This project intends to adopt a telecentric photography multiphase instrument as a tool. At first, the approaches on the measurement of dim systems such as bubble-liquid system and two phase synchronous speeds are developed. On this basis, we conduct our research on bubble swarm scale and reactor scale. The bubbles movement, meso scale structure and interaction of bubble and liquid are studied in with high superficial gas velocity close to the industrial conditions. Then the bubble swarm movement and interaction mechanisms are revealed. As to the reactor scale, we measured the phase holdup, velocity field, bubble size distribution and turbulent shear field distribution. Then obtain the interphase force mechanism model and the bubble size distribution model are obtained. After that, further establish multiphase reactor fluid mechanics model is established.in reactor scale, numerical simulation and combining experimental measurement combining are used to reveal reactor flow, dispersion and mixing mechanism in bubble column with high superficial gas velocity. Finally, a chemical engineering foundation for the design and enlargement scaleup of the high gas velocity bubble column is formed.

由于缺乏可靠的研究工具，造成了鼓泡床基础研究和工程应用脱节的现状，反应器准确设计和工程放大存在困难。本项目拟采用远心照相多相测量仪为工具，发展含气泡、暗颗粒等曝光不足多相体系的图像测量方法，同时着力实现一件仪器两种相态的同步测速；在此基础上，从颗粒群和反应器两个尺度上开展研究，在颗粒群尺度上研究接近工业条件的高表观气速时的气泡群运动、介尺度结构和相间作用，揭示气泡群运动规律和相间作用机理。在反应器尺度实验测量气液两相相含率和速度场分布、气泡粒度分布和湍流剪切场分布等，获得目前极度缺少的高气速鼓泡塔局部性质基础数据。通过气泡群的研究获得相间作用力机理模型和气泡尺寸分布模型，进一步在反应器尺度上建立多相反应器流体力学模型，数值模拟和实验测量相结合揭示反应器内两相流动、分散和混合机理。最终形成高气速鼓泡塔设计和放大的化学工程基础。

面上项目(21878297)完成了项目计划的各项研究内容：（a）发明了适用于典型工业操作条件的高气速鼓泡塔中颗粒群尺度测量的原位多相图像测速法，可以实现多相相含率、速度、气泡尺寸和湍流强度等物理量分布的同步测量；（b）采用高保真原位图像测量法测量了鼓泡塔中气泡形貌、尺寸、气含率和比表面积局部性质分布，获得了从均匀鼓泡流、过渡流到湍动鼓泡流鼓泡塔反应器的宏观和颗粒群尺度的多相流动规律；（3）使用原位视频探头同时测量局部流动特性（包括滑移速度、颗粒滞留率和颗粒加速度），并基于颗粒非稳定运动的内联数据计算悬浮颗粒上施加的总阻力系数，开发了一个使用原位图像测量法建立相间作用总阻力模型的新程序，总阻力系数与五个无量纲数（包括所有重要因素）的关系如下 ；（4）改进原位图像测量法使之更加准确并更加适应于工业操作条件下测量，包括动态光散射暗颗粒和气泡等弱反射颗粒增量技术，优化的高浓度规则颗粒和不规则颗粒自动准确识别算法、软件等，并将其推广应用到搅拌槽反应器气泡流体动力学研究。