Numerical Study on Premixed Methane–Air Flame Propagation in a Confined Vessel at Low Initial Temperature

Abstract

In this article, premixed methane–air flame propagation in a confined vessel at low initial temperature was simulated using a multistep chemical reaction mechanism. The confined vessel was a cylinder with aspect ratio of 3 with asymmetrical position of the ignition source near the side cover. The equivalence ratio and the initial temperature of the premixed unburned combustible gas were 1.0 and 150 K, respectively. The overall evolution of the flame and the flame dynamics were obtained, respectively. Through the entire flow field variation, vortex movement, and pressure wave propagation characteristics during the whole process of combustion, the flame propagation mechanism of methane combustion at low initial temperature was established finally. Results indicate that five stages are divided during the methane combustion in a confined vessel: spherical flame propagation, “fingertip” shaped flame propagation, flame “skirt edge” contacts the side wall, “crescent” flame propagation, and typical “tulip” flame ...