颗粒聚团等非均匀介尺度结构及颗粒粒径多分散是气固反应器系统的常见特征，导致流动及传热的非均匀性，但遗憾的是，现有的气固传热及固固传热模型多适用于单分散均匀系统。在更适合工业大尺度反应器模拟的粗网格及粗粒化方法中，缺乏多分散非均匀介尺度气固及固固传热封闭模型，对该模型进行研究具有重要的理论意义及工程应用价值。双分散系统是多分散系统的典型代表，因此，本项目拟基于解析到颗粒表面的直接数值模拟方法构建动态双分散气固两相流系统的微尺度气固相间传热模型。结合细网格计算流体力学-离散单元法在更大尺度上模拟双分散气固两相流动与传热，基于理论分析及过滤方法构建双分散介尺度气固及固固传热系数封闭模型。掌握粒径比及固含率比等对传热的影响规律，揭示非均匀介尺度结构对双分散系统传热的影响机理，探索传热的介尺度效应。为涉及双分散（并可方便的拓展至多分散）气固两相流的反应器优化、设计和放大提供理论依据和技术支撑。

In gas-solid reactor system, it is very common to see the meso-scale heterogeneous structures such as clusters, and the particles always have a wide particle size distribution, called polydisperse, which lead to the non-uniformity of flow and heat transfer. Unfortunately, the existing models of gas-solid heat transfer and solid-solid heat transfer are mostly applicable to the monodisperse uniform system. In the coarse-grid and coarse-grained methods which are more suitable for large-scale industrial reactor simulation, there is a lack of heterogeneous meso-scale gas-solid and solid-solid heat transfer model for polydisperse system. However, it has important theoretical significance and engineering application value to study the meso-scale model. The bidisperse system is a typical representative of the polydisperse system. Therefore, this project plans to build a micro-scale gas-solid heat transfer model of the dynamic bidisperse gas-solid two-phase flow system based on the particle-resolved direct numerical simulation. And then, simulate the flow and heat transfer of the bidisperse gas-solid two-phase flow system on a larger scale using the fine-grid computational fluid dynamics-discrete element method. Based on the theoretical analysis and the filtering method, the meso-scale model of gas-solid and solid-solid heat transfer coefficient of bidisperse system can be established. This project aims to master the effects of particle size ratio and solid volume fraction ratio on the heat transfer, to reveal the influence mechanism of meso-scale heterogeneous structures on the heat transfer of bidisperse system, to explore the meso-scale effect of heat transfer. This project could provide theoretical basis and technical support for the optimization, design and amplification of the reactor involving bidisperse (and can be easily extended to polydisperse system) gas-solid two-phase flow.