Numerical Study on Gas-Solid Flow Characteristics in Fine Particle Bubbling Fluidized Beds
Gas-solid uniformity is the precondition to realize the sufficient gas-solid mixing, reaction, heat transfer and good flow performance in gas-solid fluidized bed.In the fluidized bed combustion system, the fluidized stagnation zone is easy to appear because of the disturbance of inelastic collision of solid particles and the wall effect.The high density and weak heat and mass transfer capacity of the bed materials in the fluidized stagnation zone easily lead to the heat transfer deviation of the heating surface, which has an adverse impact on the normal and safe operation of the system.In order to ensure the uniformity of fluidization in the fine particle bubbling fluidized bed, reduce the formation of the fluidized stagnation zone and ensure the safe operation of the heating surface, the gas-solid flow characteristics in the fine particle bubbling fluidized bed need to be systematically studied.In this work, the distributions of the solids holdup, the velocities of the particles and the thicknesses of the particle boundary layers in the fine particle bubbling fluidized beds with different reflux structures and different layouts of the heating surfaces were studied by Eulerian-Eulerian approach incorporating the kinetic theory of granular flow.Some numerical results were compared with the experimental data to verify the accuracy of the numerical simulation model.The numerical results showed that when the inlet and the outlet of the particles were located on the opposite side of the fine particle bubbling fluidized bed, the movement of the particles in the fine particle bubbling fluidized bed was more intense.At the same time, when the layout direction of the heat exchange tubes was perpendicular to the direction of the particles flowing out of the fluidized bed from the reflux port, the heat exchange tubes could enhance the disturbance of the particle flow in the fine particle bubbling fluidized bed and inhibit the formation of the particle boundary layers on the side walls.
bubbling fluidized bed reflux structure gas-solid uniformity particle boundary layer numerical simulation
Yangfan Song Xiaofeng Lu Quanhai Wang Jianbo Li Yinhu Kang
Key Laboratory of Low-grade Energy Utilization Technologies and Systems of Ministry of Education, Chongqing University,Chongqing 400044, Peoples Republic of China
国际会议
Proceeding of 2nd Conference of Circulating Fluidized Bed Boiler ( 第二届国际循环流化床锅炉会议)
青岛
英文
59-72
2019-07-19（万方平台首次上网日期，不代表论文的发表时间）