基于双流体模型的气固流态化复杂全回路系统建模与验证

The complex full-loop system in gas-solid fluidization is widely applied in industrial operation. Compared to unit simulation, mathematical modeling and simulation of complex full-loop systems play a more significant effect in systematic optimization design, guiding practical operation and realizing virtual process engineering. In a full-loop system, “particle transport” acts as a bridge to organically link individual parts together. To deeply understand special performances in a full-loop system, such as coexistence of multiple regimes, granular behaviors in dense transporting pipes and different modes of regulating flow rate, we will innovate in modeling approach and simulation technique. Firstly, formation mechanisms of meso-scale structures under various flow regimes will be investigated to extend the applicable range of existing meso-scale drag models. Secondly, granular stress model and related parameters will be analyzed and modified to improve the prediction of two-fluid model in granular behaviors in dense transporting pipe. Thirdly, porous media model will be borrowed to express the function of regulating particle flow rate by mechanical valves. Based on aforementioned improvements, we can successfully simulate complex full-loop systems in the end. This project contributes to understand relationships between individual components in a full-loop system and form scientific methodology for industrial system. Furthermore, it can set up the validating platform of theoretical models, and also prepare the ground for realization of virtual process engineering and finally guiding the industrial production.

气固流态化复杂全回路系统被广泛用于实际生产过程。较之于对单个操作单元的模拟，实现对复杂全回路系统的理论建模和模拟对优化系统设计、指导工业操作以及实现虚拟过程工程更具重要意义。复杂全回路系统以颗粒输送为纽带实现回路中各单元的有机结合。针对系统内出现的多流域共存、不同输送段中的颗粒运动行为差异以及不同物料循环模式下的流量调控方式等特征，本研究将从以下三个方面展开工作：1）探讨不同流域下的介尺度结构形成机制，拓展介尺度流动模型的适用流域；2）改进颗粒应力等模型，提高双流体模型对颗粒密相流的预测精度；3）采用多孔介质模型实施强制循环模式下的阀门控制，解决复杂全回路模拟中的物料循环调控。本项目的开展，有助于揭示气固流态化系统中各单元之间的相互作用和影响规律，形成综合全回路理论模型和实现方法检验的实用平台，可望为实现虚拟过程工程和最终真正指导工业生产提供理论基础和仿真实践。

气固流态化复杂全回路系统广泛用于能源、化工过程。较之对单个操作单元的模拟，实现对复杂全回路系统的理论建模和模拟对优化系统设计、指导工业操作以及实现虚拟过程工程更具重要意义。复杂全回路系统以颗粒输送为纽带实现回路中各单元的有机结合。针对系统内出现的多流域共存、不同输送段中的颗粒运动行为差异以及不同物料循环模式下的流率调控方式等特征，本项目探讨不同流域下的介尺度结构形成机制，建立了考虑了微观鼓泡结构的二步法介尺度曳力模型，拓展介尺度流动模型的适用流域；系统比较了常规基于KTGF的颗粒应力模型和基于密相流的颗粒应力模型，考察了璧面条件对颗粒输送的影响，确定最佳的颗粒应力模型和璧面条件, 提高双流体模型对颗粒密相流的预测精度；采用多孔介质模型实施强制循环模式下的阀门控制，解决复杂全回路模拟中的物料循环调控；基于上述研究，实现了多个全回路系统的模拟。本项目的实施，揭示了气固流态化系统中各单元之间的相互作用和影响规律，形成综合全回路理论模型和实现方法检验的实用平台，可为实现虚拟过程工程和最终指导工业生产提供理论基础和仿真实践。