【摘要】 为研究提升管高30 m、内径0.3 m的密相输运床中试装置的气固流动特性,采用计算颗粒流体力学方法,建立全循环模型。采用此方法分析了循环流率和操作气速对气固流动的影响,提升管内颗粒体积分数在轴向上呈指数型分布,在径向上呈中心低边壁高的分布,随着循环流率的增大或操作气速的减小而整体增大。通过改变立管充气,模拟的固体循环流率达到800 kg/(m~2·s),平均颗粒体积分数达到0.07,提升管内为密相悬浮上升流,相比快速流态化,速度分布无典型的"环核结构"。此外提升管内加速段长度随循环流率增大或操作气速减小而增大。结果可以为实验提供指导,以及扩展到煤气化过程模拟。更多还原

【Abstract】 In order to study the gas-solid flow characteristics of a pilot plant of dense transport bed,the computational particle fluid dynamics(CPFD) approach was employed to establish a full loop model.The diameter of the riser is 0.3 m,and its height is 30 m.Based on the method,the influences of solids circulation rate and superficial gas velocity on gas-solid flow behavior were analyzed.In the riser,an exponential distribution of the axial solids volume fraction was obtained,and in the radial direction,solids volume fraction is low at the center and high near the side wall.Besides,solids volume fraction increases as the solids circulation rate increases or the superficial gas velocity decreases.By changing the aeration rate into the standpipe,the simulated solids circulation rate reached 800 kg/(m2·s),and mean solids volume fraction reached 0.07,the dense suspension upflow flow pattern was obtained in the riser.Compared to the fast fluidization,the velocity distribution is not the typical coreannulus flow structure.In the riser,solids acceleration length increases with the increase of solids circulation rate or the decrease of superficial gas velocity.The results provide guidance for experiments and can be extended to the simulation of coal gasification process.更多还原