Kasra Farnagh - M.Sc. student of Mechanical Engineering, Shahid Beheshti University, A.C.T., Tehran, Iran.
Javad Aminian - Assistant professor, Mechanical and Energy Engineering Department, Shahid Beheshti University, A.C.T., Tehran, Iran.

Normally, the Two Fluid Method (TFM) is used for simulation of two-phase, gas-solid fluidization in fluidized beds. In this work, a new combined drag-viscosity model is proposed. Numerical simulations were performed in a finite volume scheme using the twoPhaseEulerFoam solver and its modified sub models, available in the open source software package OpenFOAM ٢.١.١. The classical semi-theoreticalfoundation of the proposed new model is at an advantage against fine-tuned sophisticated models. It can also be used for any Geldart’s group relating to the gas volume fraction at minimum fluidization. In addition, the developed model with the thanks to the supporting sub-drag models has the capability to prediction of main hydrodynamic parameters of fluidized beds in dense to dilute regimes. Validation process has been performed on a comprehensive experimental data which covered a wide range of flow regimes from dense to dilute. A comparative study of different shifting point on the momentum exchange coefficient (or friction coefficient in multiphase flows) was performed to obtain optimum results. Then, verification task has been conducted on two other experiments with different regimes, bed hydrodynamic parameters, bed geometries and Geldart’s groups. Two dimensional evaluation of some hydrodynamic parameters showed that the new proposed model could capture benefits of sub-drag and viscosity models and provide better agreement with experimental data.

Fluidization, Drag model, Viscosity model, Two fluid model