Computer Modelling of the Combustion and Extinction of Methane-Air Premixed Flames by Thermally Stable Gases

摘要

A computer model was developed to examine the chemical kinetic reaction mechanism for the combustion and extinction of premixed methane-air flames. The model contains 23 chemical species and 73 elementary reaction steps. In the present study the thermal extinction theory was investigated. The radiation heat losses and the residence times of involved species in flames can be simulated with the model. The radiation term is assumed to arise only from gaseous CO2 and H2O. Extinction of the flames was simulated using four thermally stable inert gases; carbon dioxide (CO2), gaseous water (H20), nitrogen (N2) and helium (He). According to the results obtained, the extinguishing efficiency is proportional to the molar heat capacity of the inert gas.