Four-way coupled Eulerian-Lagrangian study of phase interaction mechanism in the supersonic gas-solid two-phase flow

Supersonic gas-solid jet injection has received much attention in many industrial applications such as pneumatic conveying, powdered drug delivery, steel refining process and thermal spray coating, but it is still a challenging topic due to the complex interphase interaction in compressible flows. In this work, supersonic gas-solid two-phase flow is numerically studied under the Eulerian-Lagrangian framework. After the model validation with the experimental measurement, the inherent mechanism of supersonic gas-solid flow under the conditions of different powder feeding rates and particle diameters is explored. The results demonstrate that increasing the powder feeding rate leads to the reduction of the axial velocity and penetration ability of the particles. Especially when powder feeding rate increases to 10 kg/s, serious blockage occurs in the nozzle divergence section and the conventional supersonic flow characteristic in Laval nozzle has been substantially changed. Moreover, particle diameter largely determines the dynamic and thermodynamic characteristics of the particles. Small-diameter particles exhibit better followability to the gas phase and large-diameter particles exert non-negligible impact on the gas flow, mainly reflects in weakening the expansion ability of the gas phase. The results obtained in this work provide meaningful insight for understanding the flow characteristics of supersonic gas-solid flow and benefit the operating parameters selection in industrial applications.