Flame Imaging of Highly Turbulent Premixed Methane-Air Combustion Using Planar Laser Induced Fluorescence (PLIF) of CH (C-X)

Abstract

The article presents an investigation of CH (C-X) planar laser induced fluorescence imaging (PLIF) of highly turbulent methane-air flames inside a windowed combustor. Flame dynamics and flame growth and evolution of methane-air flames stabilized over a backward facing step at high Reynolds Number (Re) (Re = 15000 and Re = 30000) with an equivalence ratio of 0.7 are discussed. It was observed that the flame evolution was faster at Re = 30000 than that of Re = 15000. The rate of initiation or formation of wrinkles, detachment of the wrinkles and burnout of the burned gases from the flame core increased with the increase in Re. The qualitative flame imaging shows that the width of the flame profile increases as the flame progress towards downstream and the flame becomes thinner as the turbulence level increases. An experimental methodology was developed to optimize the system for excitation, detection of the CH C-X band and post-processing the PLIF images.