Verification of a Microscale Drag Model Considering the Effect of Gas-Structure Interface Via Fine-Grid Two-Fluid Simulations

Sharp interfaces between the dilute phase and dense phasesarewidely reported in both experimental and computational studies ofgas-solid fluidized beds. Therefore, the microscale drag modelthat could account for the influence of the interface is importantto the accurate prediction of gas-solid dynamics. This studyevaluates the performance of one of such models using fine-grid two-fluidsimulations at different grid resolutions. It is found that the simulationresults obtained using the interface drag model are closer to theexperimental results than those obtained using the homogeneous draglaw. The interface drag model can reduce the high demand for gridresolution in fine-grid two-fluid model (TFM) simulation with smallparticles. It is also found that the difficulty in accurately simulatingdifferent fluidized beds is different for homogeneous drag models,i.e., turbulent bed > circulating bed > bubbling bed. However,usingthe interface drag model, one can obtain grid-independent resultsfor different fluidized beds at a coarser mesh resolution. The interfacedrag model is also helpful in attenuating the blurriness of the interfacebetween the dilute and dense phases as the grid size increases.

Automated summary

Sharp interfaces between dilute and dense phases are commonly observed in gas-solid fluidized beds. A microscale drag model that considers the interface influence is important for accurately predicting gas-solid dynamics. This study evaluated the performance of such a model using fine-grid two-fluid simulations and found that the interface drag model yields results closer to experimental data compared to the homogeneous drag law. The interface drag model also reduces the grid resolution requirement for simulating small particles in fine-grid two-fluid models.