Numerical simulation of reacting and non-reacting liquid jets in supersonic crossflow

Canonical jet in supersonic crossflow (JISC) studies have been widely used to study fundamental physics relevant to a variety of applications. While most JISC works have considered injection of gases, liquid injection is also of practical interest and introduces additional multi-scale 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 implemented with a volume of fluid scheme to capture the liquid breakup and turbulent mixing at high resolution. The results compare the effects of the jet momentum ratio and freestream temperature on the 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 (TKE) 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.