Effect of Impurities on Lean Laminar Hydrogen–air Flames

Abstract

Simulations of the effect of addition of H, O, OH, HO2, and H2O2 on the structure and propagationof laminar flames in lean (12 and 15%) hydrogen-air flames are performed at pressures of 1 and 6 bar. Itis found that impurities in concentrations of no more than 0.1% do not have any significant effect on laminarburning velocity. When initial temperature is increased to 400 K, the effect of impurities becomes evenweaker. Among the impurities under study, only the addition of OH reduces the laminar flame velocity. Theweak effect of the impurities is attributed to fast formation of intermediate products via reactions involving Oand H atoms without noticeable change in heat release rate. An increase in initial pressure to 6 bar does notchange the effect of impurities.