SPRAY PROCESS MODELING IN METAL MATRIX COMPOSITE POWDER PRODUCTION

Abstract

solid particulate material (typically ceramic particles) is co-injected together with the atomization gas to be impacted on the liquid metal lamellas/droplets in flight. Thus, a three-phase spray flow is formed. The spray process is simulated based on a multi-scale model. On the macro-scale, an Eulerian‐Lagrangian‐ Lagrangian model is employed. According to the simulation results, high gas velocity (above 100 m/s) and particle number concentration (in the order of 10 2 /mm 3 ) can be maintained in the secondary atomization region, e.g., 30‐40 mm below the nozzle, where the metallic droplets and ceramic particles have been mixed fully. Numerical results from the macro simulation provide a background and initial conditions for the mesoscale simulation. On the meso-scale, the particle-laden gas flow around a metallic droplet is investigated based on an Eulerian‐Lagrangian model. The particle-droplet impact efficiency, found related to relative Stokes number (St) and Reynolds number (Re), should be always above 90% for a spherical droplet of 125 „m diameter along its flight path, due to high St and Re (both in the order of 10 2 ‐10 3 ). The interaction between the metallic droplets and the ceramic particles is described quantitatively based on a particle-droplet (spherical) impact model. However, the particle incorporation rate into the metal droplets is overpredicted in comparison to experimental findings, probably due to neglecting particulate reinforcement penetration efficiency and the influences from the metallic lamella/droplet deformation and break-up.