Multiscale modeling and analysis of transverse jet atomization and evaporation under high-temperature and elevated-pressure conditions
Abstract
This study develops an enhanced multiscale hybrid algorithm, VOF-LPT-EVAP (Volume of Fluid–Lagrangian Particle Tracking–Evaporation), for simulating liquid jet atomization and evaporation in crossflow under realistic gas turbine conditions. Current multi-scale hybrid modeling efforts primarily focus on momentum coupling, with limited attention to energy transfer and phase change, which are critical in high-temperature, high-pressure environments. To address this gap, we extend an established VOF-LPT (Volume of Fluid–Lagrangian Particle Tracking) framework by integrating phase-change mechanisms, including interface evaporation and a superheated droplet flash evaporation model. A high-precision Gaussian-based source term distribution technique ensures stability and conservation in the Eulerian–Lagrangian coupling. The solver is first validated against experimental data for water and Jet A fuel jets in a high-temperature (696.15 K) crossflow. Results show good agreement in spray morphology, jet trajectory, and droplet Sauter Mean Diameter (SMD) distribution. A subsequent parametric study investigates the effects of inlet gas–liquid velocity, crossflow temperature (300–1250 K), and pressure (4–7 bars) under afterburner conditions. Increasing the liquid-to-gas momentum ratio enhances jet penetration and delays column breakup, while a higher gas Weber number promotes surface instability via Kelvin–Helmholtz waves. Elevated crossflow temperature intensifies droplet evaporation, reducing the overall droplet count and SMD while increasing fuel vapor concentration. Although increased pressure can moderately suppress evaporation, it generally leads to a smaller spray field SMD. Flow field analysis reveals the governing role of counter-rotating vortex pairs and a transition point in the wake, which dictate droplet transport and breakup location. The VOF-LPT-EVAP algorithm proves to be a high-fidelity tool for capturing the complex multiscale physics of atomizing and evaporating sprays, providing detailed insights into the design and optimization of combustion devices operating in realistic gas turbine environments.