The Energy Spectrum Analogy Breakup (Sab) Model for the Numerical Simulation of Sprays

This paper proposes a new model for liquid droplet breakup. The size of the droplets produced in each breakup regime is computed using new correlations based on the assumption that a breakup energy cascade exists and follows a path similar to that of the turbulent energy cascade. This spectrum analogy breakup (SAB) model allows linking the size of turbulent eddies and the size of droplets formed in each breakup regime (i.e., bag, multimode, shear or thinning, and catastrophic regimes). It may be seen as a unified version of the fractioning induced per acceleration model (Habchi et al., 1997) with the stochastic Lagrangian model (Gorokhovski, 2001). The SAB model has been implemented in the large eddy simulation (LES) AVBP code and validated using experiments. A satisfactory quantitative agreement has been obtained for the statistics on droplets sizes and their velocities and for Weber numbers ranging from 68 to 383, corresponding to most of the breakup regimes already identified by the experiments. In addition, issues related to LES of sprays using a Lagrangian approach with refined grids and a high volume fraction of liquid are discussed and solutions are proposed.