Numerical Simulation on Metallic Droplet Deformation and Breakup Concerning Particle Morphology and Hollow Particle Formation During Gas Atomization

The deformation and breakup of metallic droplets during gas atomization were simulated using a volume of fluid (VOF) approach that considered droplet cooling and solidification. The correlation between the typical powder morphology and droplet breakup behavior was established to guide the preparation of spherical powder particles. The results showed that upon increasing the ratio of aerodynamic to viscous force of the droplet, the formation of spherical particles was enhanced, while upon decreasing this ratio, the expected droplet breakup mode changed or only droplet deformation occurred. Several typical scenarios were observed from the numerical simulations of the hollow particle formation and evolution process, e.g., open hollow film formation, film closure, bubble centrifugation, and bubble detachment. By increasing the gas velocity or droplet temperature, a higher non-equilibrium Laplace pressure or lower viscous forces was achieved, which separated the bubbles from the interior of the droplet.