Large-eddy Simulation of Ethanol Spray-Air Combustion and Its Experimental Validation

Large-eddy simulation of spray combustion is under its rapid development. Different combustion models were used by different investigators. However, these models are less validated by detailed experimental data. In this paper, large-eddy simulation (LES) of ethanol spray-air combustion was made using an Eulerian-Lagrangian approach, a subgrid-scale kinetic energy stress model, and a filtered finite-rate combustion model, neglecting the sub-grid scale reaction rate. The simulation results are compared with experimental dada in the literature and validated in detail. The LES obtained statistically averaged gas temperature is in much better agreement with the experimental results than Reynolds averaged (RANS) modeling using the most complex probability density function (PDF) equation combustion model. The instantaneous LES results show the coherent structures of the shear region near the high-temperature flame zone and the fuel vapor concentration map, indicating that the droplets are concentrated in this shear region. The instantaneous temperature, oxygen and carbon dioxide concentration maps show the close interaction between the coherent structures and the combustion reaction.