Combustion of NH₃–CH₄ blend in a Coaxial Swirl Burner

¹ TEMI Laboratory, Gafsa University, 2121 Gafsa, Tunisia
² ICARE CNRS, Combustion, Aerothermal, Reactivity and Environment Institute, 4571 Orleans 45071, France

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Ammonia is a promising carbon-free fuel for decarbonizing the energy sectors. However, implementing it in combustion systems is limited by difficulties in maintaining flame stability and controlling nitrogen oxide (NO_x) emissions. This study investigates the turbulent non-premixed combustion of NH₃-CH₄ blend in a coaxial swirl burner under atmospheric pressure, using experimental diagnostics. Two configurations are examined: (i) high swirl number (Sn = 1.4) and (ii) low swirl number (Sn = 0.8). Flame structure and stability was analysed via OH* and NH₂* chemiluminescence imaging of four blend cases. Results show that high swirl enhances mixing of fuel and oxidizer resulting in a compact flame anchored to the burner. In contrast, low swirl shows better flame stability, the flame is more diffused toward radial and axial direction. However, it indicates higher NO_x emissions.