A New Subgrid Breakup Model for LES of Spray Mixing and Combustion
Characterizing the inflow conditions, especially of droplet distribution at the computational inlet is one of the challenging aspects for a successful multiphase Large Eddy Simulation (LES). Here, we investigate spray modeling by simulating the experiments of acetone spray mixing by Chen et al. (2006). In the experiments, the turbulent spray is generated by a shear driven nebulizer and is carried through a 7L/D circular pipe into a mixing chamber [see Fig. 1(a)]. Two separate simulation campaigns are performed. In the first set of simulations, only the internal-flow within the injector is studied using breakup modeling. These breakup simulations are used to assess a new multi-scale breakup procedure by comparing the predicted droplet profiles at the injector exit plane with data. Experimental data at the injector exit plane is shown to be dilute and therefore, in the next set of simulations, this dilute spray exiting into the mixing chamber is simulated using different inflow profiles. Comparison with data using two different subgrid mixing models is used to highlight key features of the far field development of the spray and the gaseous flow.
KeywordsLarge Eddy Simulation Proper Orthogonal Decomposition Unstable Mode Droplet Size Distribution Breakup Model
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