The Effect of Air Preheating on a Sudden-Expansion Turbulent Diffusion Air-fuel Flame

摘要

An axisymmetric sudden-expansion geometry of a co-flowing methane-air diffusion flame is considered to investigate the effect of air preheating on pollutant formation using k - ε turbulence and β-PDF combustion models. The governing equations are solved by iterative numerical approach using Finite Volume Method and a second-order upwind scheme. NO and CO_2 concentration and peak com-bustor temperature as well as combustor efficiency are studied in this paper. The obtained results show that air preheating increases NO formation and maximum temperature in the combustor. Air preheating improves the combustor efficiency and save fuel as well.