【摘要】 气相场基于欧拉法,颗粒相采用离散单元法(DEM),同时考虑气固流动、传热传质以及化学反应,构建了基于CFD-DEM法的稠密气固系统热转化过程的并行数值模拟方法及平台,并对实验室规模的流化床半焦燃烧过程进行了研究。通过准三维流化床中单颗粒燃烧模拟对所建立的模型进行了验证,其后考察了不同过量空气系数下的三维流化床半焦燃烧,获得了颗粒流型、空隙率、温度、组分浓度等分布,结果表明高气量增加了反应初始阶段半焦燃烧速率,加速了半焦温度的升高。更多还原

【Abstract】 The gas phase is modelled by Eulerian method and the solid phase by discrete element method(DEM). The gas-solid flow, heat and mass transfer, and chemical reaction are simultaneously considered. A parallel numerical method and platform for heat conversion process of dense gas-solid system is established, which is applied to the simulation of char combustion in a lab-scale fluidized bed. Based on the validation by the single particle combustion in a quasi-three dimensional(3 D)fluidized bed, the combustion processes in a 3 D fluidized bed under different air ratios are studied.The gas-solid flow pattern, profiles of voidage, temperature, and gas composition are obtained. The results show that char combustion rate of initial reaction stage increases with the increasing air ratio,accelerating the rise of char temperature.更多还原