메탄 산소 연소에 있어서 화염 소화에 대한 연구

Abstract

ABSTRACTOxy-methane nonpremixed flames diluted with CO 2 were investigated to clarify impact of radiation heat loss and chemical effects of additional CO 2 to oxidizer stream on flame extinction. Flame stability maps were presented with functional dependencies of critical diluents mole fraction upon global strain rate at several oxidizer stream temperatures in CH 4 -O 2 /N 2 , CH 4 -O 2 /CO 2 , and CH 4 -O 2 /CO 2 /N 2 counterflow flames. The effects of radiation heat loss on the critical diluent mole fractions for flame extinction are not significant even at low strain rate in nonpremixed CH 4 -O 2 /N 2 diffusion flame, whereas those are significant at low strain rate and are negligible at high strain rate (> 200 s -1 ) in CH 4 -O 2 /CO 2 and CH 4 -O 2 /CO 2 /N 2 counterflow flames. Chemical effects of additional CO 2 to oxidizer stream on the flame extinction curves were appreciable in both CH 4 -O 2 /CO 2 and CH 4 -O 2 /CO 2 /N 2 flames. A scaling analysis based on asymptotic solution of stretched flame extinction was applied. A specific radical index, which could reflect the OH population in main reaction zone via controlling the mixture composition in the oxidizer stream, was identified to quantify the chemical kinetic contribution to flame extinction. A good correlation of predicted extinction limits to those calculated numerically were obtained via the ratio between radical indices and oxidizer Lewis numbers for the target and baseline flames. This offered an effective approach to estimate extinction strain rate of non-premixed oxy-methane flames permitting air infiltration when the baseline flame was taken to nonpremixed CH