Large-Eddy Simulation of Particle Size Distribution Effects on Turbulence in Sprays

Abstract

In this work Large-Eddy Simulation and Lagrangian Particle Tracking methods are used to improve understanding of the dynamics of sprays for a range of particle loadings (i.e. 0.001 - 0.002 of volume fraction). We consider a subsonic particle laden round gas jet at Re = 104 and Ma = 0.3. The initial slip velocity between the particulate and the carrier phases is +0.25Uexit. The computational particle sizes are distributed in a range of Stokes numbers, 0.1 l Stp l 10. Thereby, interaction between the turbulent flow and the particle spectrum can be studied. Two particle mass loadings ψ = 0.3 and 0.6 are investigated corresponding to strong and very strong two-way momentum coupling. The results demonstrate that the mean Stokes number of the particle size distribution and the mass loading have a significant role in the observed dynamics of the jet. The relationship between the probability distribution function of the particles to gas slip velocities and the observed intermediate and large scale behaviour including mixing is pointed out.