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实验表明,出口结构对循环流化床提升管内截面平均空隙率等流动分布有明显影响。目前对提升管出口的二维模拟研究比较多,但大多忽略出口结构对流动行为的影响。本文对内径76mm、高10.2 m的循环床提升管进行了二维模拟,研究不同出口结构对提升管内流动的影响。结果表明,出口结构对提升管出口处的固相循环通量、出口附近轴向浓度分布有明显影响:在侧边出口条件下,径向浓度分布结果呈现非对称分布,固相速度径向分布在出口附近有明显减小。模拟结果与实验值对比也印证了上述结论。
Experiments show that the outlet structure has a significant effect on the flow distribution such as the average void fraction of the inner cross section of the circulating fluidized bed riser. At present, there are many two-dimensional simulations on the export of riser, but most of them neglect the influence of export structure on the mobile behavior. In this paper, a two-dimensional simulation of a circulating-bed riser with an inner diameter of 76 mm and a height of 10.2 m was carried out to study the influence of different outlet structures on the flow inside the riser. The results show that the outlet structure has a significant effect on the solid-phase circulation flux at the outlet of the riser and the axial concentration distribution near the outlet. In the case of the side outlet, the radial concentration distribution presents an asymmetric distribution and the radial distribution of the solid velocity There is a marked decrease near the exit. The simulation results and experimental results also confirm the above conclusion.