Experimental and Computational Study of the Burning Rates of Ultra-Lean toModerately-Rich H2/O2/N2 Laminar Flames with Pressure Variations

摘要

By using the counterflow flame technique, laminar flame speeds of H2/O2/N2mixtures have been experimentally determined in the fuel stoichiometric range of ultra-lean to moderately-rich, oxygen concentration range of 7.4 to 30 molar percent of the oxidizer, and pressure range of 0.2 to 2.25 atm. These results are then compared with the numerically-determined values obtained by using several existing H2/O2 kinetic schemes. Results show that, while these kinetic schemes accurately predict the propagation speeds of high-temperature flames, they substantially underpredict those of low temperature flames. Furthermore, while the experimental pressure exponents of the mass burning rates exhibit a minimum-point, parabola-like behavior with increasing pressure, indicating the initial, negative influence of the H-O2 termination reaction and the subsequent availability of a positive channel which facilitates radical production, the calculated results fail to show the increasing trend in the pressure range investigated.