Reaction Mechanisms Testing with Spatial and Thermal Resolutions of Methane/Air Flames

Spatial and Thermal Resolutions of Methane/Air Flames

Abstract

Spatial and thermal dispersals of hydroxyl (OH), formaldehyde (CH₂O), and other minor species have been acquired using various detailed reaction mechanisms in the weak flame of stoichiometric methane and air mixture at ambient pressure.  The weak flame was simulated inside a microflow combustor with a prescribed temperature profile which releases a very small amount of heat. A wide reaction zone (~ 1 cm) was observed for methane and air flames compared to normal/conventional flames. Detailed oxidation analysis was carried out based on the normal and weak flames simulations. The computational flame structure was assessed with the experimental results available in the existing literature. Numerical modeling under the experimental conditions with various detail mechanisms predicts a similar wide reaction zone. However, the species production and consumption temperatures were observed to vary for the different mechanisms used in present studies. The GRI mech 3.0 shows a typical two-peak heat release rate profile. The initial breakdown of fuel is vital for such scatter. The production of OH radicals governs the initial breakdown of fuel at intermediate temperatures. The present investigation is pretty useful in understanding the chemistry of intermediate species for different fuel-air mixtures specially at intermediate temperatures 800–1200 K.