Interface-Coupled Volume of Fluid and Lagrangian Particle Tracking Method for Pharmaceutical Spray Atomization Analysis

This study presents a novel computational approach that bridges Eulerian Volume of Fluid (VoF) and Lagrangian Particle Tracking (LPT) methods for simulating pharmaceutical spray atomization. Our interface-transition methodology includes a three-step process: identification of discrete fluid structures, derivation of their physical attributes, and conditional transformation into particle-based representations. We investigate the effects of swirling number (S) and injection angle (θ) on spray distribution patterns and breakup mechanisms. Results demonstrate that increasing S (0.15-0.4) and θ (15°-40°) enhances atomization, with optimal dispersion occurring at the highest values (S=0.4, θ=40°). Primary breakup height shows a linear relationship with S, while secondary breakup follows an inverse power-law relationship (S^-1). At higher swirl numbers, secondary breakup becomes dominated by centrifugal forces rather than injection angle. These findings provide valuable design principles for developing more efficient pharmaceutical delivery systems with precise control over spray characteristics.