液固循环流化床换热器中固体颗粒分布

利用CCD图像测量与数据处理系统对多管液固循环流化床换热器中的两相流动特性进行了研究。探讨了下管箱中的分布板结构对固体粒子的体积分数分布、固体粒子的速度分布,以及液固两相流压降的影响。实验结果表明:在循环流化床换热器进口段安装适当结构的多孔板分布器,即多孔板的面积小于床层截面积,且床中心处的遮挡面积大于边缘处的遮挡面积,可以有效地提高固相速度的均匀程度,在较高流速下,能较好地改善固体颗粒在管束中的不均匀分布。

Distribution of solid particle in liquid-solid circulating fluidized bed

The CCD image measurement and data processing system was used to study two-phase flow properties of multi-pipe circulating fluidized bed. The influence of distributor structure on the holdup and velocity distribution of particles and the pressure drop of the liquid-solid two-phase flow was discussed under the certain height and structure of the inlet and outlet chambers. Experimental results show that the perforated-plate distributors, which are properly arranged in the inlet of chamber of the liquid-solid circulating fluidized bed heat exchanger, with the area of perforated-plate smaller than that of the bed, and the shedding area in the center of the bed larger than that in the edge of the bed, can effectively improve the uniform distribution of the velocity of particles, and decrease the nonuniform distribution of particles in the pipe bundle under high flow rate.