Facile and cost-effective droplet cooling and solidification model for gas atomization: Influence of atomizing gas composition on droplet non-equilibrium solidification behavior--颗粒学报PARTICUOLOGY

Facile and cost-effective droplet cooling and solidification model for gas atomization: Influence of atomizing gas composition on droplet non-equilibrium solidification behavior

Yaxian Shi^a, Xinggang Li^b *, Changchun Ge^a *

a Institute of Powder Metallurgy and Advanced Ceramics, University of Science and Technology Beijing, Beijing, 100083, China
b Institute for Advanced Materials, North China Electric Power University, Beijing, 102206, China

10.1016/j.partic.2026.02.010

Volume 111, April 2026, Pages 120-135

Received 30 October 2025, Revised 30 January 2026, Accepted 10 February 2026, Available online 12 February 2026, Version of Record 18 February 2026.

E-mail: xing-gangli@163.com; ccge@mater.ustb.edu.cn

Highlights

• A CFD-thermodynamics coupled model predicts solid fraction for droplet cooling.

• Predictive equations for cooling rate were successfully established.

• Kinetic energy distribution of atomizing is directly correlated with particle size.

• Nitrogen shows superior heat transfer efficiency during droplet solidification.

Abstract

A comprehensive droplet cooling and solidification model was developed to quantitatively predict the evolution of solid fraction in atomized droplets during gas atomization under rapid solidification conditions. The model integrates computational fluid dynamics with thermodynamic phase diagram calculations through modified Scheil-Gulliver-based solidification scheme, allowing for fully coupled tracking of droplet cooling and phase transformation dynamics during flight. The fitted equation relating droplet cooling rate to particle diameter obtained from the model exhibits both a functional form and cooling trend consistent with literature-reported, as well as with the cooling rates estimated from the experimentally measured secondary dendrite arm spacing of powder samples, thereby validating credibility and effectiveness of the proposed model. Key findings demonstrate that nitrogen atomization has significantly higher cooling rates compared to argon. While argon exhibits superior kinetic energy for droplet fragmentation, the enhanced thermal conductivity of nitrogen substantially improves heat transfer efficiency, leading to markedly reduced solidification distances. Experimental characterization confirms distinct microstructural differences of powders: argon-atomized powders display coarser grain structures with dendritic features, whereas nitrogen-atomized powders exhibit homogeneous fine crystalline structures and smoother surface morphology. The study establishes quantitative predictive models for cooling rates and solidification distances, providing a robust framework for optimizing gas atomization parameters.

Graphical abstract

Keywords

Gas atomization; Nonequilibrium solidification; Modified scheil-gulliver model; Computational fluid dynamics (CFD)

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