二维喷动床CFD-DEM模拟中曳力模型的影响

CFD-DEM已经广泛应用到喷动床的研究中,其模拟的准确性与用于处理颗粒-流体相互作用的曳力模型密切相关。为了探究不同曳力模型对喷动床CFD-DEM模拟结果的影响,基于非结构化网格的喷动床仿真,使用7个曳力模型分别对锥底喷动床内气固两相运动进行了数值模拟。综合床层压降、喷动高度和颗粒速度特性三个方面,Wen-Yu模型和Gibilaro模型预测的气固两相运动最剧烈,其次是Di Felice模型、Syamlal-O’Brien模型、Gidaspow模型和Huilin-Gidaspow模型,BVK模型预测的气固两相运动最平缓。由于模拟的气固两相体系属于密相体系,Huilin-Gidaspow模型的光滑过渡函数没有产生效果,所以Gidaspow模型和Huilin-Gidaspow模型在各个方面的预测结果基本一致。

Influence of drag force models on CFD-DEM simulation of spouted bed

CFD-DEM has been widely used in the study of spouted beds,and the simulation accuracy of which is closely related to the drag models applied to handle the particle-fluid interaction force.With the aim of investigating the influence of different drag models on the simulation results of spouted bed,especially for the spouted bed discretized with unstructured girds,the gas-solid dynamics of a spouted bed with a conical base were simulated in seven drag models,respectively.Considering pressure drop,spouted height and particle velocity characteristics,Wen-Yu model and Gibilaro model predicted the most intensive gas-solid dynamics,followed by Di Felice,Syamlal-O''Brien,Gidaspow and Huilin-Gidaspow models,and the gas-solid dynamics predicted by BVK model was the gentlest.Because the two-phase system in this study was particle-dense,the smooth transition function of Huilin-Gidaspow model did not work and the results predicted by Gidaspow and Huilin-Gidaspow model were exactly the same.