Modeling Drop Deformation Effects in the Euler-Lagrange Prediction of Liquid Jet in Cross Flow

Abstract

Accurate prediction of spray atomization process using an Euler-Lagrange (EL) approach is challenging because of high volume fraction of the liquid phase in dense regimes. This would in reality displace a remarkable portion of the gaseous phase which is commonly ignored in the standard EL approaches. In addition, deformation of droplet due to the interaction of aerodynamic force, surface tension and viscous forces is typically neglected in modeling dense sprays. In this work, to capture the volumetric displacement effects using an EL approach, the spatio-temporal changes in the volume fraction of the gaseous phase are taken into account. This leads to zero-Mach number, variable density equations that give rise to a source term in both momentum and continuity equations. It is shown that the continuity source term increases the velocity and dynamics of the carrier phase close to the nozzle. However, owing to the jet spread and dispersion of droplets, these effects decrease further downstream. In order to quantify the droplet deformation effects, different models are compared together with an experimental data. Different breakup regimes are studied in order to identify the best model for each regime. The shape deformation effect is isolated by performing a single droplet injected into the cross flow with flow conditions similar to the bag-type breakup. A significant deviation in the motion of droplet is observed compared to a case where deformation is neglected.