宽粒径分布气固两相流的粗网格模拟：介尺度相间曳力模型

循环流化床是能源与资源高效清洁利用的核心反应器之一，它的基本特点是固体颗粒直径一般具有较宽的分布和存在介尺度结构（颗粒聚团）。介尺度结构特性与粒径分布特性紧密相关，并且介尺度结构特性在很大程度上决定反应器的操作特性。本项目针对重大研究计划中反应器层次的介尺度结构，通过分析气－固两相流系统内在的控制机制间的协调来确定系统的稳定性条件，建立合理的介尺度模型来量化粒径分布特性对循环流化床中介尺度结构特性和气－固相间曳力的影响，然后把介尺度模型与连续介质模型耦合，通过计算机模拟系统研究粒径分布特性对气－固两相流颗粒混合与偏析等流动特性的影响。这一研究有望为流化床反应器的放大与设计提供理论依据，为实现重大研究计划中突破煤炭高效清洁利用、重劣质油加工等过程放大难题这一目标做出贡献。

Circulating fluidized bed (CFB) reactor is one of the most important reactors in the high efficient and clear utilization of energy and resources. CFB is characterized by the existence of meso-scale particle clustering structure and wide particle size distribution. The nature of particle size distribution, to a large extent, determines the characteristics of meso-scale structures and therefore the operating characteristics of CFBs. Focusing on the meso-scale structures at reactor level, present proposal attempts to establish a meso-scale model to characterize the relation between particle size distribution and meso-scale structure, and then to determine the effective inter-phase drag force. The target is achieved via analyzing the dominant mechanisms and their compromise in the determination of stability condition of the studied system. The proposed meso-scale model is then integrated with continuum model to systematically study the effects of particle size distribution on the hydrodynamics of CFBs, such as mixing and segregation. Present study is expected to be very useful in the design and scale-up of CFB reactors, and therefore, contributing to the realization of the target of whole national project.