Experimental and numerical analysis of a turbulent spray flame structure

An experimental and numerical study of an academic n-heptane/air lab-scale jet spray burner is presented. The objective is to provide new insight on turbulent spray flame complex structures similar to those encountered in industrial combustors by joint experimental and numerical diagnostics. Experimental measurements include PDA for air velocity and droplet size as well as velocity and OH-PLIF images for the flame analysis. Numerical simulations consist in Large Eddy Simulation (LES) coupled to Discrete Particle Simulation for the dispersed phase. The comparison between experiment and simulation confirms the capability of LES to reproduce the gaseous and liquid flow structure in both non-reacting and reacting cases with good accuracy. The lifted stabilized spray flame exhibits a complex shape due to interactions between turbulence, chemistry and evaporation. A detailed analysis shows that both partially-premixed and diffusion flames are present, depending on the capacity of droplets to evaporate. Furthermore, an attempt is made to identify the processes leading to two-phase flame stabilization.