Numerical analysis of airflow turbulence intensity effect on liquid jet trajectory and breakup in two-phase cross flow

Abstract

Spraying liquid jets in the transverse airflow is suitable for creating tiny droplets in the combustion chamber. This paper numerically investigated the effect of airflow turbulence intensity on liquid jet penetration and breakup. The large-eddy simulation method is used for numerical solutions. The level set model and volume of fluid (VOF) model are combined for two-phase crossflow modeling. Elliptical and circular nozzles with different aspect ratios and diameters were used to obtain liquid jet trajectories. Other trajectory equations due to different nozzle shapes were obtained for laminar flow. It is shown that the liquid jet trajectory depends on momentum ratio and dimensionless length. For turbulence flow, as results show, when the turbulence intensity of the transverse airflow increases, the energy in the flow vortexes also increases, so the breakup point approaches the liquid jet location. Also, as the turbulence intensity of the transverse airflow increases, the liquid jet trajectory and its penetration depth are not affected significantly because the dynamic energy of turbulence fluctuations is negligible compared to the air main flow. i.e., at 10 %, turbulence intensity equals 1 percent of the primary energy dynamics of the main flow.