循环流化床中的气固两相传热模型

Influence of Particle Cluster on Gas-Solid Heat Transfer in A Circulating Fluidized Bed

循环流化床中存在着分散固体颗粒的连续上升气相和相对紧密的颗粒团两部分 ,颗粒团聚物对气固两相传热有着重要的影响。采用拟 Boltzmann动力学方法描述循环流化床中颗粒团的动力学行为 ,建立了循环流化床中气固两相间传热过程的理论模型 ,对气体表观流速、固体颗粒循环率等对气固传热系数沿床高分布规律的影响进行了分析和讨论。模型计算结果与参考文献中的实验数据进行了比较 ,两者符合较好。图5表 1参 1

In this paper, a modeling approach to the heat transfer in a circulatin fluidized bed (CFB) provides a physical model that describes the dependence of local heat transfer between gas and solid on the flow profile, the Bolzman like kinetic theory was used to describe the hydrodynamic behavior of particles in CFB. The effects of superficial gas velocity and solid mass fluxes on the local heat transfer between gas and solid were discussed for different conditions. The numerical results show that the gas solid heat transfer coefficient rapidly decreases with an increase in distance along the axis. The particle clusters have great influence on the gas solid heat transfer. The model results are found to compare favorably with the experimental data available in the literature. Figs 5, table 1 and refs 11.