基于表面更新的高粘聚合物拉伸场诱导成膜与脱挥机制研究

高粘聚合物降膜脱挥系统引入特殊导流构件可实现拉伸成膜，拉伸场诱导成膜和促进传质脱挥的运行机理尚不明确。拟以聚酯缩聚脱挥过程为研究背景，在申请人前期研究基础上，对拉伸场诱导成膜及其稳定性进行系统研究。考察拉伸成膜过程中速度分布、拉伸场分布、成膜时空演化，建立导流构件-拉伸场-高粘流体成膜-表面更新-强化脱挥之间的关系，获得拉伸成膜的稳定性相图，以期调控和强化脱挥效果。基于实验和计算流体力学模拟方法，揭示拉伸成膜产生机制、液膜不稳定性流动机制和表面更新诱导机理的关联效应。本项目将促进气液两相传质理论与方法的完善和高效脱挥反应器的设计与放大。

The falling film devolatilization system with particular guiding parts for highly viscous polymer can achieve stretching film, and the mechanism of film formation by stretching field and mass transfer intensification is not clear. The PET condensation process is proposed to be the research background. On the basis of the previous studies, the film formation induced by stretching field and its stability are investigated. The velocity distribution, stretching field distribution, temporal and spatial evolution of film formation by stretching field are studied. The relationship between guiding part, stretching field, film formation, surface renewal and devolatilization intensification can be obtained to get the stability diagrams, in order to control and enhance the devolatilization performance. Based on experimental study and computational fluid dynamics simulation, the mechanisms of film formation, flow instability and induced surface renewal are uncovered. This project will promote the improvement of the theory and method of gas-liquid two-phase mass transfer, and improve the design and scale-up of high efficiency devolatilization reactor.