非对称混炼流场共混聚合物混沌混合与反应机理研究

The internal batch mixer is an important reactor for polymer reactive processing, in which the mixing and reactive mechanisms are very complex. From current researches, we have known that the fluid in the internal batch mixer has typical chaotic mixing characteristic, which has great effect on the reactive mechanism for the polymer blends. Therefore, the present project focuses on the study of the chaotic mixing and reactive mechanisms under the asymmetric flow field using the nonlinear chaotic dynamics theory. The project contents cover: ① The chaotic mixing characteristics and their evolutions in the internal batch mixer will be employed by means of Poincaré section, finite-time lyapunov exponents (FTLE) and Lagrangian coherent structures (LCS) and so on. At the same time, the spatio-temporal topology of the flow structure will be established. The qualitative informations of local stretching and folding rules will be provided. Moreover, the temporal and spatial chaotic mixing mechanisms of the polymer blends in the mixer will be revealed. ② The theory models of reactive processing system in the mixer will be established to directly connect the relations of "fluid velocity-chaotic mixing-macroscopical reaction". The effect of evolution process for the chaotic mixing of the reactive polymer blends on the reactive mechanism in the mixer will be studied. Furthermore, the relationship between the chaotic mixing intensity and reaction rate of polymer blends in the mixer will be revealed.③ A new high-efficient internal batch reactor with asymmetric rotors will be devised and manufactured based on the chaotic dynamics theory. And the analytical equations describing the geometric modeling of the asymmetric rotors will be put forward. The significance of this project covers: the new theory system of designing the internal batch mixer will be enlarged based on the nonlinear chaotic dynamic theory. An important theoretical foundation will be provided to achieve the precision control of reaction process.

密炼机是一种重要的聚合物反应加工设备，其混合和反应机理非常复杂。当前研究表明，密炼机流体具有鲜明的混沌混合特性，流体的反应机制与混沌混合密切相关。本课题拟引入非线性混沌理论，开展非对称混炼流场下共混聚合物混沌混合与反应机理研究。研究内容包括：①采用数值模拟和实验相结合，利用Poincaré映射、有限时间Lyaponuv指数场和拉格朗日拟序结构等，研究密炼机共混聚合物流体混沌演变过程，构建混沌流场时空拓扑结构，定量表征流场局部拉伸和折叠规律；揭示密炼机共混流体的时间和空间混沌混合机理。②建立"流体速度-混沌混合-宏观反应"有效联系的反应加工系统理论模型，研究混沌演变过程对共混反应流体反应机制的影响；揭示混沌混合强度与反应速率的内在关联。③设计和制造新型高效非对称转子密炼机反应器，给出转子几何造型解析表征方法。研究意义：丰富密炼机反应器设计理论体系，为实现反应过程精密控制提供重要的理论基础。

密炼机是一种重要的聚合物反应加工设备，其混合和反应机理非常复杂。本项目从非线性动力学角度，开展了非对称混炼流场共混聚合物混沌混合与反应机理研究。主要研究工作如下：①建立了密炼机内单相和共混聚合物流体流动的物理模型。采用Poincaré映射、Lyaponuv指数和粒子可视化等动力学表征技术，对密炼机流体的动力学特性开展了系统研究；分析了密炼机流体的周期、拟周期和混沌等演变规律；利用椭圆不动点分析，发现了密炼机转子壁面附近流体的独特混合机制。②利用有限时间Lyaponuv指数（FTLE）和拉格朗日拟序结构（LCS）开展了基于拉格朗日理论框架的密炼机流体输运的动力学机理研究。分析了转子几何构型和加工条件对密炼机二维和三维流场FTLE和LCS分布的影响机制，刻画出密炼机流体输运的动力学边界，获得了密炼机流场的几何学和动力学特性。在此基础上，利用拉格朗日拟序结构理论，调控宏观流场的流型结构，设计了新型四转子/螺杆混合设备，显著提升了设备的混合效率。③建立了“流体速度-混沌混合-宏观反应”有效联系的反应加工系统理论模型，从宏观角度揭示聚合物流体混沌混合与聚合物反应特性内在关联。研究了混炼加工设备几何参数和工艺参数等对混沌流场局部和整体反应速率的影响机制；定量表征了混沌流场强度和反应速率的内在关联。此外，基于拉格朗日理论，找出了反应流体输运特性、温度分布规律和反应速率之间的作用机制。本项目为丰富聚合物加工设备设计的理论体系，实现反应过程精密控制提供重要的理论参考。