Real-fluid effects on laminar diffusion and premixed hydrothermal flames

Abstract

This paper is aimed to investigate the real-fluid effects on both diffusion and premixed laminar hydrothermal flames. The real-fluid effects are examined in three aspects, including the equation of state (EOS), thermodynamic, and transport properties. Results show that, for diffusion flames, the introduction of non-ideal EOS is the most significant adjustment as it modifies the flame location, while the correction of thermodynamic and transport properties has minor impacts on the flame structure. For premixed flames, the real-fluid models have limited influence on the temperature and species distributions but significantly affect the flame speed, which is mainly due to the density modification of the unburned mixture by the real-fluid EOS. Finally, the Lewis numbers are derived and the evaluation results show that laminar hydrothermal flames are sensitive to the Lewis number assumption and the non-unity Lewis number method can properly describe the differential diffusion effects for hydrothermal flames.