循环流化床内稠密气固两相流动的数值模拟  

NUMERICAL SIMULATION OF THE DENSE TWO-PHASE FLOW IN A GAS-PARTICLE CIRCULATING FLUIDIZED BED

作　　者：刘向军[1] 徐旭常[2] 

机构地区：[1]北京科技大学热能系,北京100083 [2]煤的清洁燃烧技术国家重点实验室,清华大学北京100084

出　　处：《中国电机工程学报》2003年第5期161-165,共5页Proceedings of the CSEE

基　　金：国家重点基础研究专项经费项目(G1999022208-8)~~

摘　　要：颗粒团聚是稠密气固两相流动中的一个重要现象,该文定义了颗粒团聚合力的概念来表征稠密气固两相流动中颗粒所受到的团聚效应,对单个颗粒进行了全受力分析,得到了聚合力的线形模型表达式。采用聚合力的线形模型,将两相流场分为稀相区和浓相颗粒团,将颗粒团视为整体 离散相,文中数值模拟了循环流化床内的稠密气固两相流动,得到了床内颗粒团分布、颗粒团大小、床内空隙率、气相速度、颗粒相速度的详细分布,揭示了循环流化床内稠密气固两相流场的规律,以及循环流化床内两相流场的核心-环形流动结构。计算结果与前人实验结果相符并表明,采用该模型及其算法模拟循环流化床内稠密气固两相流动是可行的。Particle clustering is an important phenomenon in dense particle-gas two-phase flow. In this paper, a binding force is introduced to present the impact of particle clustering and a linear expression of this binding force is obtained by summarizing all the forces acted on one particle inside a cluster. Dividing the dense two-phase flow field in a gas-particle circulating fluidized bed into gas-rich dilute phase and solid-rich cluster phase, the dense gas-particle two-phase flow field in a circulating fluidized bed (CFB) is numerically studied. The particle cluster is treated as one discrete phase and the trajectory model is used to describe the behavior of clusters in every time step. Detailed results on cluster structure, cluster size, bed vodiage, gas velocity, and particle velocity are obtained, and the non-uniformity of two-phase flow field and the core-annulus flow structure in a CFB can be successfully simulated. These calculated results are in agreement with experiment ones. It shows that these models and algorithm are feasible and can be used to study the dense two-phase flow in a CFB efficiently.

关 键 词：循环流化床锅炉 气固两相流动 数值模拟 数学模型 

分 类 号：TK229.66[动力工程及工程热物理—动力机械及工程]