粘稠体系同心双轴搅拌微观混合的表征、机理及模型化

As a novel technology, coaxial mixer obtains extensive market recognition on the conditions with high and variable viscosity for its advantages of energy conservation, high efficiency, flexible operation and strong adaptability. At present, researches on coaxial mixer are focused on its macroscopic characters, which results in the poor recognition of micromixing mechanism. Hence, this research aims to accomplish the characterization, mechanism and modeling of micromixing of coaxial mixer in viscous media on the basis of theoretic analysis and experimental tests. During the study of this project, the reaction system and method for the micromixing performance characterization of viscous media will be first developed, and then the factors and rules influencing the micromixing performances of coaxial mixer will also be analyzed and summarized, which is beneficial to reveal the micro-mechanism of macroscopic factor control. In addition, based on the experimental determination of segregation index and the consideration of special structure and operation of coaxial mixer, relational expressions about local special energy dissipation rate and micromixing time will be established. In some degree, the success of this research will rich the comprehension to the connotation of coaxial mixer in viscous media and promote the change of coaxial mixer from experience design to theory design and rule design.

作为一种新型技术，同心双轴搅拌凭借低耗高效、灵活可调、适应性强等优点，在中高粘、变粘等场合被迅速认同。但当前对同心双轴搅拌的研究更多集中于宏观特性方面，缺少对其微观混合机理的认识。为此，本项目以实现粘稠体系同心双轴搅拌微观混合的表征、机理及模型化为目标，综合运用实验测试与理论推导等手段，探索设计兼顾大小分子扩散差异的适于粘稠体系微观混合性能表征的反应体系和方法，明确同心双轴搅拌微观混合性能的影响因素及其统计规律，揭示宏观性能调控的微观机理，同时建立体现同心双轴搅拌结构与运行特征的基于离集指数测定的局部比能耗散率和微观混合时间的专门关联式。本项目的成功将丰富对粘稠体系同心双轴搅拌微观混合内涵的认识，并推动同心双轴搅拌从经验设计向理论设计、规则设计迈进。

作为一种新型技术，同心双轴搅拌凭借低耗高效、灵活可调、适应性强等优点，在中高粘、变粘等场合被迅速认同。但以往研究更着重于宏观混合，而对于快速反应体系，影响产物品质的主要是微观混合。为此，本项目研究典型同心双轴搅拌器宏观混合性能的基础上，着重进行了其微观混合性能的研究。首先，针对同心双轴搅拌系统具有两套独立搅拌装置与运行参数的特点，定义了其特征直径与特征转速，并进行了其功率与宏观混合特性的研究，确定同向运行模式对降低同心双轴搅拌器的功率消耗和促进宏观混合有利。其次，分析比较了不同的微观混合性能表征方法，优选碘化物-碘酸盐平行竞争反应体系来计算离集指数表征同心双轴搅拌器的微观混合性能，该表征体系在粘稠体系下具有操作简单、结果易于分析、实验结果重现性好以及经济等优点。最后，进行了典型同心双轴搅拌器微观混合性能的研究，揭示了转速、运行模式、加料时间、加料位置、桨型、粘度等不同因素对双轴搅拌器微观混合性能的影响规律，同样发现同向运行模式对提高同心双轴搅拌器的微观混合性能更有益。此外，还分析了大双叶片搅拌器的微观混合性能，优化了其结构与运行参数。本项目丰富了宽适应性同心双轴搅拌器的研究范畴，深化了对其宏观混合与微观混合性能的认识，对推动同心双轴搅拌从经验设计向理论设计、规则设计迈进有益。

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