【摘要】 通过离散元软件LIGGGHTS重现球体的重力堆积过程,建立三维随机堆积床几何模型.利用大涡方法结合双温度模型以及EBU-Arrhenius燃烧模型,模拟了甲烷/空气预混气体在堆积床内预混合燃烧过程.通过将模拟结果与实验数据对比验证了模型的有效性,在此基础上对随机堆积床内部的火焰分布结构、火焰面形状及温度分布规律等进行了分析.模拟结果表明:在燃烧后期,堆积床内的小球温度要高于同一高度上气体的温度,这体现了多孔介质良好的蓄热能力;壁面与轴线间的火焰面高度差远远小于无多孔介质的管内燃烧情况,表明随机堆积床可以通过分割火焰来提高燃烧的均匀性和稳定性.更多还原

【Abstract】 Three dimensional random geometric structure of pellets packed bed was modeled using the discrete element software LIGGGHTS. Large eddy simulation method,two-temperature model and EBU-Arrhenius combustion model were employed to simulate the premixed combustion process of methane-air in the randomly packed bed. The calculated results are compared with experiment data to verify effectiveness of the model. The structure and the shape of the flame and the temperature distribution in the packed bed were analyzed. The simulation results show that the temperature of solid is higher than that of gas on the same height of the packed bed during the late stage of combustion,which reflects a good thermal storage capacity of the porous medium. The height difference of the fame surface between the tube wall and the center in the packed bed is much smaller than that in tube without porous media,which suggests that the flame is divided by the packed bed and then the uniformity and stability of the combustion within a porous medium are improved.更多还原