偏心搅拌反应器内自由表面湍流流动与混合特性研究

As an important measure for improving the mixing efficiency, the eccentric agitation method has aroused extensive research and attention in academic fields. Flow field characteristics are the key factors that affect the performance of stirred reactors. It was experimentally found that, under the turbulent flow conditions, the fluid within eccentric reactor undergoes obvious surface deformation, but no relevant studies have been considerably carried out. In this project, the free surface turbulent flow characteristics and its effect on the liquid-liquid mixing and solid-liquid suspension in eccentrically stirred reactors are studied. Firstly, through the establishment of the modeling and simulation method of the free surface agitation flow field, the study of the free surface turbulent flow characteristics in the eccentric stirred reactor and its influencing factors are performed. Subsequently, the species transport model and the volume of fluid (VOF) model are coupled to build a mathematical model that can reflect the effect of the liquid surface deformation on the liquid-liquid mixing process. In this way, the free-surface mixing characteristics of the eccentric stirred reactor is studied. Finally, a coupled VOF and Eulerian multiphase flow model is built to study the solid-liquid suspension characteristics in the free-surface eccentrically stirred reactor. At the same time, corresponding experimental measurements are also conducted so as to verify the numerical simulation results, and to evaluate the reliability and validity of the models established in this project. The results of this project are expected to provide theoretical fundamentals for the study of the flow and mixing characteristics of stirred reactors, and lay the foundation for the application of eccentric agitation in the process industry.

偏心搅拌作为改善混合效果的一种有效方式，引起了学术界广泛的研究和重视。流场特性是决定搅拌反应器性能的关键因素,现有研究发现湍流时偏心搅拌反应器内的流体存在明显的液面变形，但未深入开展考虑液面变形时流动特性研究。鉴于此，本项目拟对偏心搅拌反应器内的自由表面湍流流动特性及其对反应器内液液混合和固液悬浮的影响进行研究。通过建立自由表面搅拌流场的数值模型和模拟方法，研究偏心搅拌反应器内的自由表面湍流流动特性及其影响因素；将组分传输模型与VOF模型相耦合，建立反映液面变形影响的液液混合过程的数学和数值模型，研究偏心搅拌反应器内的混合特性；建立耦合的VOF和Eulerian多相流模型，研究自由表面偏心搅拌反应器内的固液悬浮性能。此外，还开展实验测试研究，用于验证数值模拟结果,同时评价所建模型的可靠性及有效性。项目预期成果可为搅拌流场与混合的研究提供理论依据，同时为偏心搅拌在过程工业中的应用奠定基础。

该项目以搅拌设备，尤其是偏心搅拌设备，为研究对象，建立了搅拌流场的分离涡模拟方法，对搅拌槽内流体的流动与混合规律进行了研究，并就提高混合效率提出了一些措施。. 在该项目的资助下，取得了以下主要成果：建立了搅拌流场的分离涡模型和模拟方法，与VOF模型相结合，研究了湍流状态下偏心搅拌槽及无挡板中心搅拌槽内的自由液面流场特性，分析了重力在自由表面湍流搅拌流场模拟中的重要性,，模拟了自由液面的变形情况；采用所建立数值模型和模拟方法，研究了初始时处于分层状态的互溶流体的混合规律；自主设计了六直叶网格状圆盘涡轮式搅拌桨，采用分离涡模型研究了该桨的湍流流场特性与混合性能，通过与标准涡轮桨的对比，验证了其优越性；开发设计了一类错位叶片搅拌桨，研究了桨叶宽度对流场特性的影响规律以及错位六直叶圆盘涡轮桨的气液混合性能，还模拟研究了双层错位六叶半圆管盘式涡轮桨搅拌槽内的气液混合性能；设计了一种半圆管挡板搅拌槽，分析了湍流流场特性，能提高流体速度分布均匀程度，增大流体的轴向和切向速度以及湍动能，而且具有一定的节能功效；设计了一种提升式搅拌器，和一种自激振动型柔性叶片搅拌器；开发了基于AMR单片机混沌映射控制的混沌搅拌控制系统，获批了发明专利。所取得了研究成果丰富了搅拌混沌混合研究内容。