Thermoacoustic instabilities of coaxial jet combustor; computational studies using LES

Swirl combustion is encountered in many engineering applications since it provides efficient fuel burning. Experimental studies of turbulent swirl combustion poses challenges due to unsteady nature of the combustion phenomenon. Therefore, computational approaches are a promising alternative for the numerical studies of supersonic combustion. The present studies concerns the computational studies of swirl combustion, particularly the effect of the injection scheme on the combustion efficiency and flame stability. Therefore, the effect of the air-fuel ratio on the combustion efficiency and flame stability is subject of investigation. The combustion efficiency is assessed based on the temperature developed inside the swirl combustor. The computations are carried out using the large-eddy simulation (LES) approach along with the flamelet combustion model. The analysis reveals the unsteady nature of the flame and thus, its departure from the core of the combustor. The analysis also reveals the presence of a region of high level of temperature, NO and CO₂, inside the combustor.