通过实验和模拟方法考察了高气速,高固体通量循环流化床提升管内B类颗粒的流动情况.根据EMMS(energy minimization multi—scale)理论提出了改进的曳力修正表达式,同时与传统的曳力模型如Gidaspow,O’Brien—Syamlal,Koch—Hill—Ladd的计算结果进行了比较。结果表明:使用本文提出的修正曳力模型的计算模拟结果与实验值得到了较好的吻合。
Gas-solid flow in high density circulating fluidized bed riser at high gas velocity and comparatively high solid flux using Geldart B particles was investigated by experiments and Computational Fluid Dynamics (CFD) simulation. Owing to the key role of the drag force between two phases in CFD, drag force models in the literatures were reviewed and the modified drag force coefficient Hd based on EMMS models was obtained, and then Gidaspow, O'Brien-Syamlal, Koch-Hill-Ladd and EMMS models were validated under our test conditions. The results predicted by EMMS drag model showed the best agreement with the experimental axial average pressure drop and apparent solid volume fraction due to the cluster. The newly proposed Hd equation can predict well the flow structure under high gas velocities and high solid flux rate.