Numerical Simulation of Reacting and Non-Reacting Liquid Jets in Supersonic Crossflow
Michael Ullman, Shivank Sharma, Venkat Raman
TL;DR
The paper tackles the challenge of understanding liquid jet in supersonic crossflow (JISC) with atomization, evaporation, and finite-rate chemistry at $M_ ty \approx 4.5$. It employs a volume-of-fluid (VOF) method with adaptive mesh refinement (AMR) to resolve liquid breakup and turbulent mixing, coupled to a 43-species gas-phase mechanism in Cantera alongside a stiffened-gas liquid model. The results show that jet penetration and mixing scale with the jet momentum ratio $J$, while heat release concentrates along the bow shock and near-wall regions; evaporative cooling quenches reactions near injection, leading to low overall combustion efficiency by the domain exit. The study clarifies the multiscale physics of reacting liquid JISC and highlights the challenges in promoting combustion, suggesting that future work should explore injection strategies and higher enthalpy conditions to enhance ignition and mixing in high-speed propulsion contexts.
Abstract
Canonical jet in supersonic crossflow studies have been widely used to study fundamental physics relevant to a variety of applications. While most JISC works have considered gaseous injection, liquid injection is also of practical interest and introduces additional multiscale physics, such as atomization and evaporation, that complicate the flow dynamics. To facilitate further understanding of these complex phenomena, this work presents multiphase simulations of reacting and non-reacting JISC configurations with freestream Mach numbers of roughly 4.5. Adaptive mesh refinement is used with a volume of fluid scheme to capture liquid breakup and turbulent mixing at high resolution. The results compare the effects of the jet momentum ratio and freestream temperature on jet penetration, mixing, and combustion dynamics. For similar jet momentum ratios, the jet penetration and mixing characteristics are similar for the reacting and non-reacting cases. Mixing analyses reveal that vorticity and turbulent kinetic energy intensities peak in the jet shear layers, where vortex stretching is the dominant turbulence generation mechanism for all cases. Cases with lower freestream temperatures yield negligible heat release, while cases with elevated freestream temperatures exhibit chemical reactions primarily along the leading bow shock and within the boundary layer in the jet wake. The evaporative cooling quenches the chemical reactions in the primary atomization zone at the injection height, such that the flow rates of several product species plateau after x/d=20. Substantial concentrations of final product species are only observed along the bow shock-due to locally elevated temperature and pressure-and in the boundary layer far downstream-where lower flow velocities counteract the effects of prolonged ignition delays. This combination of factors leads to low combustion efficiency at the domain exit.