曳力模型对喷动床气固两相流数值模拟结果影响的介尺度分析

Mesoscale Analysis of Influence of Drag Model on Numerical Simulation Results of Gas-solid Two-phase Flow in Spouted Bed

为探究不同曳力模型在喷动床稠密气固两相流数值研究中的适用性及准确性,基于开发的介尺度格子玻尔兹曼-离散单元法(LBM-DEM)耦合流动程序,分别采用Syamlal-O’Brien、Gidaspow、EMMS三种曳力模型对微型喷动床进行了数值模拟。比较分析了不同曳力模型下的结果差异,并通过实验验证了各模型预测结果的准确性。研究表明:三种曳力模型都能完整展现喷动床内气泡演化及颗粒流化的全过程,其中EMMS模型的整体预测结果与实验值最相吻合,能较好展现床内非均匀流化过程的细节,模型整体适用性最好;Gidaspow模型在均质流态的气泡演化过程中更具优势;Syamlal-O’Brien模型所计算的曳力值始终偏高,需注意规避可能引起的边壁效应影响。以上研究结果及方法可为广泛领域稠密流体-颗粒两相系统研究提供参考。

In order to explore the applicability and accuracy of different drag models in the numerical study of dense gas-solid two-phase flow in spouting beds,based on the developed coupled flow program of mesoscale Lattice Boltzmann discrete Element method(LBM-DEM),three traction models of syamlal-O'Brien,Gidaspow and EMMS were used to perform a numerical simulation of the micro-spout bed.The results under different drag models were compared and analyzed,and the accuracy of prediction results of each model were verified by experiments.The results show that the three drag models can completely show the whole process of bubble evolution and particle fluidization in a spouting bed.Among them,the EMMS model has the best overall applicability that the overall prediction results are most consistent with the experimental results,which can better show the details of the non-uniform fluidization process in the bed.Gidaspow model has more advantages in bubble evolution of homogeneous flow state.The drag force value calculated by Syamlal-O'Brien model is always on the high side,so attention should be paid to avoid the possible side-wall effect.The above research results and methods can provide reference for the study of dense fluid-particle two-phase system in a wide range of fields.