Numerical simulation on metallic droplet deformation and breakup concerning particle morphology and hollow particle formation during gas atomization
(1. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China;
2. China Machinery Institute of Advanced Materials (Zhengzhou) Co., Ltd., Zhengzhou 450001, China;
3. Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
4. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
5. China United Gas Turbine Technology Co., Ltd., Beijing 100016, China)
2. China Machinery Institute of Advanced Materials (Zhengzhou) Co., Ltd., Zhengzhou 450001, China;
3. Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;
4. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;
5. China United Gas Turbine Technology Co., Ltd., Beijing 100016, China)
Abstract: 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.
Key words: droplet breakup; hollow particle; particle morphology; viscous force; metal powder; gas atomization