摘要：Abstract
A novel structure‐based drag model was proposed to study the hydrodynamics of bubbling fluidized beds (BFBs) operated with ultrafine cohesive particles by considering local heterogeneous flow structures. Firstly, a local structure parameters model capturing the internal flow structures of the studied system was built by balance equations and empirical formulas and the solutions (i.e. local structure parameters) of this model solved by global search algorithm were evaluated in terms of hydrodynamics, energy consumption, and voidage. Then the local structure parameters were employed to derive the structure‐based drag model. Lastly, three drag models (i.e. the structure‐based drag model, Gidaspow model, and Syamlal‐O'Brien model) were investigated and incorporated separately into the two‐fluid model, where the simulation results were also separately compared with available experimental data. The comparison shows that Gidaspow and Syamlal‐O'Brien drag models failed to predict the solid volume fraction profiles. However, the error analysis results of the structure‐based drag model indicate the average absolute relative error of solid volume fraction in the radial direction is 7.04 % and 5.64 % at the height of 0.1 m and 0.2 m respectively, which exhibits promising predictions. Thus, it is feasible to simulate the BFBs with cohesive particles through the combination of the structure‐based drag model with the two‐fluid model.
A novel structure‐based drag model incorporated into a two‐fluid model framework aiming to simulate the hydrodynamics of bubbling fluidized beds operated with ultrafine cohesive particles is presented. It can reasonably capture the local heterogeneous flow structure of the studied system and shows promising predictions in solid volume fraction.
