Effect of Stefan flow on the drag force of single reactive particle surrounded by a sea of inert particles

Abstract

Single reactive particle is generally surrounded by a sea of inert sand particles in thermo-chemical conversion process of solid fuels inside fluidized bed reactors. The drag force of the reactive particle under such special condition is affected by the combination of Stefan flow from the reactive particle, particle Reynolds number (Re), and solid holdup (c). This work quantifies this combinational effect via particle-resolved direct numerical simulations. It is found that the outward Stefan flow weakens the drag force, while the inward Stefan flow strengthens the drag force. The effect of Stefan flow becomes weak as c or Re increases. The variation of Re has negligible effect on the reduction of the drag force when c is relatively high. Finally, a drag correlation considering the joint influences of Stefan flow, Re and c is proposed based on the simulation data.