Particle Dynamics in Flake‐Laden Droplets Impacting on a Liquid Film
Yasuhiro Saito, Akihiro Kurogi, Takahiro Okabe, Taimei Miyagawa, Minori Shirota, Yoshiya Matsukawa, Hideyuki Aoki, Masatoshi Daikoku, Junichi FukunoABSTRACT
Flake orientation and distribution strongly affect the appearance of metallic coatings. This study numerically investigates flake particle dynamics in a droplet impacting on a preexisting liquid film using coupled discrete element method–volume of fluid (DEM–VOF) simulations. The impact‐induced radial flow governed particle migration, whereas the initial particle configuration strongly affected migration and rotation. A thinner liquid film enhanced radial flow and promoted outward migration. Correlations for the maximum radial position and flake orientation were developed by extending those for solid‐surface impact and were examined for a shear‐thinning coating liquid. The results clarify the roles of liquid‐film thickness, particle configuration, and liquid rheology in flake dynamics during droplet–film impact.