Evaluation of a bubble-structure dependent drag model for the simulation of bubbling fluidization with Geldart A particles

• A bubble-structure-dependent drag model is applied to simulate Geldart A particles.
• Predicted results show a better agreement with experimental data.
• Distribution of bubble fraction, velocity and voidage in emulsion phase is analyzed.

The reasonable prediction on the hydrodynamics behaviors in bubbling fluidized beds with Geldart A particles has been an important issue as a result of the lack of scale resolution, although there are some progresses in the modeling of bubbling fluidized beds with Geldart B and D particles. In this work, a bubble-structure-dependent (BSD) drag model is developed and applied to the simulation of bubbling fluidized beds with Geldart A particles under the framework of the two-fluid model. The heterogeneous flow in the control volume is resolved into the local homogeneous flow and the structural parameters are directly employed to calculate the drag coefficient to describe the impact of meso-scale structures. The results demonstrate that the predictions by the BSD drag model show better agreements with experimental data than those using the conventional drag models. Meanwhile, the predicted local structural parameters including bubble fraction, velocities and voidage in emulsion phases reveal the lateral non-uniformity.

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