Effect of Droplet Size and Breakup on Spray Shape: A Priori Study Using Large-Eddy Simulation

Droplet breakup and size effects in a turbulent carrier flow are commonly encountered problems. To simulate a realistic spray pattern, the droplet size distribution and its time-evolution need to be modeled. Here, we present a priori results on the effect of droplet size on spray shape using Large-Eddy Simulation and Lagrangian Particle Tracking. Results of non-atomizing and atomizing sprays in a turbulent droplet laden jet at Reynolds number 104, Mach number 0.3 and Weber numbers below 15 are compared. The simulations show that a new, compact atomization model that models the breakup as a Poisson process with droplet resonance frequency as the rate parameter, can be used to control the atomization time and thereby the spray shape and structure. Consequent droplet size effects on turbulent mixing are discussed and quantified.