The influence of density ratio on the primary atomization of a turbulent liquid jet in crossflow

In this paper, we study the impact of density ratio on turbulent liquid jet in crossflow penetration and atomization if all other characteristic parameters, i.e., momentum flux ratio, jet and crossflow Weber and Reynolds numbers, are maintained constant. We perform detailed simulations of the primary atomization region using the refined level set grid method to track the motion of the liquid/gas phase interface. We employ a balanced force, interface projected curvature method to ensure high accuracy of the surface tension forces, use a multi-scale approach to transfer broken-off, small scale nearly spherical drops into a Lagrangian point particle description allowing for full two-way coupling and continued secondary atomization, and employ a dynamic Smagorinsky large eddy simulation approach in the single phase regions of the flow to describe turbulence. We compare simulation results obtained previously using a liquid to gas density ratio of 10 for a momentum flux ratio 6.6, Weber number 330, and Reynolds number 14,000 liquid jet injected into a Reynolds number 740,000 gaseous crossflow to those at a density ratio of 100, a value typical for gas turbine combustors. The results show that the increase in density ratio results in a noticeable increase in jet penetration, change in drop size distribution resulting from primary atomization, change in drop velocities generated by primary atomization in the crossflow and jet direction, but virtually no change in drop velocities in the transverse direction. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.