气体－多组分颗粒相间作用机理与组分颗粒动力学模型的研究

The anisotropic kinetic theory of multitype particles is established to describe the transfer and exchange of fluctuation kinetic energy and momentum between the particle phases based on molecular dynamics in dense gas-solid two-phase flow,incorporating with Chapman-Enskog iterative approach. The two-fluid Euler-Euler model for dense gas-solid two-phase flow is proposed which coupled with large eddy simulation for gas turbulence. The momentum and energy transfer and dissipation are studied due to the collision of mulitype particles on the basis of the collision dynamics of particles. The dense gas-solid two-phase flow and mixing synergy mechanism are performed in fluidized beds. The interactions between different particle phases, particle and particle in the phase, and particle and gas are investigated. The system of multitype particles in circulating fluidized bed is consisted by ash particles and calcium oxide particles. The characteristic of two group particles flow in a fluidized bed is recorded by a CCD high-speed video camera. The influence of anisotropic distribution of particle fluctuating velocity on the structure of fluidized bed is investigated. This study is not only for establishing the interaction and synergy mechanism between gas-solid two phases, but also for developing a foundation for predicting the flow behaviors of gas-solid two phases in fluidized beds.

本项目将以提升管反应器内高浓度气固两相流动为研究对象，基于分子动力学，建立多组分颗粒碰撞动力学，研究不同颗粒组分之间动量和能量的传递规律。采用Chapman-Enskog迭代法，建立组分颗粒颗粒动理学，揭示不同颗粒组份相间动量及脉动能量之间的传递和耗散规律。结合气相大涡模拟，建立高颗粒浓度气固两相欧拉-欧拉双流体模型，研究流化床反应器稠密气固两相流动与混合协同规律，研究组分颗粒与组分颗粒、组分内颗粒与颗粒、颗粒与气体之间的相互作用。以灰颗粒-石灰石颗粒构建双组份颗粒循环流化床试验平台。采用CCD高速摄像仪测量双组份颗粒流动特性，研究流化床反应器内颗粒脉动速度各向异性分布对流化床结构的影响。模拟与实验研究流化床内气固两相相间作用机制和协同规律，为正确预测流化床反应器内气固两相宏观流动过程奠定理论基础。

本项目将以高浓度气固两相流动为研究对象，基于分子动力学，建立多组分颗粒碰撞动力学，研究不同颗粒组分之间动量和能量的传递规律。建立组分颗粒颗粒动理学，揭示不同颗粒组份相间动量及脉动能量之间的传递和耗散规律。结合气相大涡模拟，建立高颗粒浓度气固两相欧拉-欧拉双流体模型，研究流化床反应器稠密气固两相流动与混合协同规律，研究组分颗粒与组分颗粒、组分内颗粒与颗粒、颗粒与气体之间的相互作用。以灰颗粒-石灰石颗粒构建双组份颗粒循环流化床试验平台。采用CCD高速摄像仪测量双组份颗粒流动特性，研究流化床反应器内颗粒脉动速度各向异性分布对流化床结构的影响。研究结果表明：颗粒－颗粒之间的相互作用和气体颗粒相间曳力的作用都是引起颗粒运动过程中脉动能量的耗散主要原因，而气体颗粒相间曳力的作用则是引起颗粒脉动各向异性的最主要因素。具体表现为，由于颗粒能量的耗散，在流动中产生颗粒团聚物，且颗粒直径越小，气体颗粒相间曳力的作用的影响越强。气相脉动强度主要受颗粒直径的影响，小尺寸颗粒能够弱化气相脉动，而大尺寸颗粒的作用下气相脉动则增强。颗粒直径越大，颗粒尾涡影响越大，气相脉动的各向异性特征越明显。气体－颗粒相间作用引起的颗粒脉动耗散的不均匀性，形成了颗粒脉动速度的各向异性特征。颗粒直径越小或者颗粒密度越低，颗粒脉动各向异性越显著。两组分颗粒中颗粒质量流率越高、颗粒的直径及密度越高，组分之间颗粒－颗粒碰撞过程的动量及能量交换越多。模拟与实验研究流化床内气固两相相间作用机制和协同规律，为正确预测流化床反应器内气固两相宏观流动过程奠定理论基础。本项目研究共发表SCI收录论文7篇，获得教育自然科学二等奖1项。