Shock-Induced Atomization and Vaporization of Liquid Fuel Droplet Clouds

This study examines the breakup and vaporization of liquid fuel droplets and droplet clouds subjected to shock waves, under conditions relevant to high-speed propulsion. A high-fidelity Euler-Euler diffuse-interface framework is employed, solving the six–equation system with stiffened–gas equations of state and a p-T-g thermodynamic relaxation model to capture liquid–vapor phase change with vapor advection into the carrier gas. Simulations were performed for isolated droplets of varying diameters, droplets in heated environments, and droplets embedded in air-hydrogen mixtures to mimic multiphase conditions encountered in advanced propulsion systems. These single-drop configurations serve as building blocks toward the analysis of droplet clouds. Both monodisperse and polydisperse clouds were considered, enabling quantification of inter-droplet interactions, wake coupling, and vapor-field overlap in shock-driven multiphase flows. The results demonstrate the progression from isolated droplets to droplet-cloud systems, establishing a systematic understanding of atomization, vaporization, and mixing mechanisms across scales relevant to high-speed propulsion applications.