Curvature Effects on Flame Structure of Hydrogen/Air Rich Premixed Flame

Abstract

The effects of flame curvature on the fuel consumption rate has been studied by means of 2-D numerical calculation with detailed chemical kinetics and accurate transport properties for a rich hydrogen-air mixture. It has been found that the local fuel consumption rate increases at the low-temperature side of flame portion where the flame develops curvature. The full use of the numerical data has been made to understand the cause of this increase. It has been found that the supply rate of H by molecular diffusion to the reaction zone is accelerated, which eventually produces the increase in OH concentration leading to this increase. The same trend of increase of fuel consumption rate with the flame curvature has been observed in the detailed 3-D simulation of a hydrogen jet lifted flame, and then the mechanism discussed in this study is one of the key mechanisms to understand the structures of turbulent premixed flames.