Comprehensive numerical analysis of high-speed kerosene gel jet atomization under periodic disturbance

To meet the increasing demands for high energy density and safety in aerospace propulsion, gel propellants have drawn significant attention due to their dual solid–liquid characteristics. However, their high viscosity and complex rheology suppress interfacial instabilities and hinder jet breakup, posing critical challenges to efficient atomization. This study develops a high-fidelity numerical framework coupling the VOF method, large eddy simulation (LES), and adaptive mesh refinement (AMR), incorporating a thixotropic shear-thinning model based on experimental data for 5 % organic kerosene gel. Considering the strong mechanical vibrations in rocket engines, the primary atomization behavior under periodic perturbations with varying amplitude and frequency is systematically investigated, with a focus on jet evolution, breakup mechanisms, droplet characteristics, and mixing efficiency. Under high-speed injection, periodic forcing intensifies upstream core instability and promotes downstream fragmentation, generating numerous fine droplets. Increased perturbation amplitude enhances radial spreading and multiscale breakup, while frequency primarily adjusts droplet size uniformity but contributes little to penetration, with a saturation effect observed. Despite large number of small, slow droplets are generated near the jet core and upstream, the jet remains largely dominated by an unbroken liquid core and ligaments. Compared to kerosene, the gel exhibits significantly poorer atomization performance, producing larger, slower, and more localized droplets due to its rheological resistance to instability growth and spatial dispersion. This work provides quantitative insights into the atomization dynamics of gel fuels and establishes a theoretical foundation for rheological control strategies in propulsion applications.