An inertial number regulated stress model for gas-particle flows with particle friction and volume fraction gradient

In this study, a solid stress model that can be used in both dilute and dense regimes for simulation of gas-particle flows with comprehensive considerations of friction and the effect of local solid volume fraction gradient is proposed. In the dilute regime, solid stress is closed by a modified kinetic theory that accounts for the effect of particle friction and volume fraction gradient. In the dense regime, solid stress is closed by the inertial number model. The transition from dilute to dense regimes is realized by using a dimensionless parameter chi, which is a function of the inertial number Is. This new model is validated with experimental data and discrete particle simulation from spout-fluid bed and bubbling fluidized bed. When compared with the traditional kineticfrictional stress model, this new model improves the transition from dilute to dense regimes and the particle velocity predictions in both beds.

Automated summary

In this study, a new solid stress model is proposed for simulating gas-particle flows in both dilute and dense regimes, taking into account friction and the effect of local solid volume fraction gradient. The model closes solid stress using a modified kinetic theory in the dilute regime and an inertial number model in the dense regime. The transition between dilute and dense regimes is achieved by using a dimensionless parameter chi that is a function of the inertial number Is. Experimental data and discrete particle simulation are used to validate the model. The new model shows improved transition and particle velocity predictions compared to the traditional kinetic-frictional stress model in both spout-fluid bed and bubbling fluidized bed.