Numerical Investigation of Wide Continuous Particle Size Distribution on the Supersonic Powder Loading Oxygen Jet

Supersonic oxygen-powder jet injection has spanned wide range of operations in chemical engineering. However, the ubiquitous polydispersity of solid powder known to exert different flow behavior than the monodisperse counterpart has not been revealed. In this work, numerical simulation of the supersonic oxygen-powder jet injection via the Laval nozzle is performed under the Eulerian-Lagrangian framework to explore the impact of wide continuous size distribution of solid phase on the gas-solid hydrodynamics. Specifically, the gas phase is solved using the Eulerian method, while the particle motion is tracked under the Lagrangian framework. The numerical model is well validated with the experimental measurements. The results reveal that the blending of particles restricts the gas phase expansion, leading to the obvious reduction of gas velocity and increase of gas temperature. Additionally, a narrow particle size distribution (PSD) width corresponds to a higher proportion of large particles, inducing stronger vortices and hindering gas phase expansion. With regard to solid phase, the penetration ability of particles is significantly enhanced within the supersonic gas flow by accelerating the particle velocity to about 300 m/s. Furthermore, particles with wider PSD exhibit increased sensitivity to interphase interaction, particle-particle collisions and lift forces, resulting in higher velocities, lower temperatures along the axial direction and greater dispersion along the radial direction. Lastly, the interphase heat transfer mainly occurs in the convergent section, divergent section, and one nozzle length downstream from the nozzle exit. The findings obtained in this study offer valuable insights for industrial applications.