流化床内煤粒燃烧过程的数值模拟

COAL COMBUSTION IN A FLUIDIZED BED WITH DEM-LES SIMULATION

应用离散单元方法(DEM)对流化床内煤粒的运动进行了模拟。其中化学反应包括焦碳与O2、CO和CO2的异相反应及CO和O2的均相反应。碰撞颗粒传热是基于球体接触时的弹性变形的分析得到的。模拟预示了颗粒的非均匀流动结构对于加热、燃烧的煤粒热特性的影响,同时研究了煤粒大小、床温、流化速度对热特性的影响。

The motions of coal particles was simulated with the Discrete Element Method (DEM) in the bulling fluidized bed. The process of chemical reactions consist of the heterogeneous reactions of char with O2, CO and CO2 and the homogeneous reactions involving CO and O2. The heat transfer between the particle-particle collisions is analyzed based on the elastic deformation of the spheres during their contact. The model is used to predict the effects of the particle heterogeneous flow structure on the thermal characteristics of coal particles The effects of the diameter of coal particles, of the bed temperature and of the inlet gas velocity on the thermal characteristics are also studied.