Experimental study on characteristics of CH4/H2 oxy-fuel turbulent premixed flames

Abstract In this work, a systematic investigation was conducted on CH4/H2 oxyfuel turbulent premixed flames. The effects of hydrogen addition and CO2 concentration on turbulent combustion characteristics of methane oxy-fuel were studied. Based on planar laser induced fluorescence (PLIF) measurement of OH radical, the turbulent flame speed and flame front structure were derived. The probability density function (PDF) of curvature radius of hydrogen enriched turbulent premixed flames was found to be similar to that of cellular flames on flat burner, which identified the role of thermal-diffusive instability. Proper orthogonal decomposition (POD) was further applied to the multi-scale analysis of flame front structure. With increase in hydrogen fraction, the effect of small-scale wrinkles was enhanced by thermal-diffusive effect, which promoted the flame propagation and made the flame prone to instability.