A parametric numerical investigation of head-on ternary droplet collision

In recent years, ternary droplet collision has been proposed in some new application prospects, such as three-dimensional (3D) reactive inkjet printer. To better apply ternary droplet collision, head-on ternary droplet collision of same liquid in the gaseous environment is investigated numerically. The investigation is based on the finite volume numerical solution of the Navier–Stokes equations in axisymmetric form. Volume of Fluid (VOF) methodology and adaptive grid technique are used to capture the liquid-gas interface and the reliability of the methodology is verified by published experimental data. Head-on ternary droplet collision for a wide range of Weber number is studied. The shape and velocity field evolution of three colliding droplets (coalescence and separation) is described in detail. Moreover, the time evolution of the kinetic energy and the surface energy of three colliding droplets, the viscous dissipation and the maximum deformation are evaluated. Furthermore, based on the dimensionless flow parameters, relevant correlations determining the length of ligament, the maximum diameter of ligament, the length of bridge and the maximum radial length are also presented quantitatively. Finally, the effect of central droplet size and distance offset on the head-on ternary droplet collision are investigated, the results are also compared and analyzed. It is believed that the present work is meaningful for better applying ternary droplet collision.