Experimental Investigation on Hydrocarbon Diffusion Flames: Effects of Combustion Atmospheres on Flame Spectrum and Temperature

Radiative heat transfer is the main mode of heat transfer in various combustion processes. The distribution of radiative spectra is complicated for different flames. In this work, the spectral intensities of a hydrocarbon diffusion flame invisible (200 similar to 900 nm), near-infrared (900 similar to 1 700 nm) and middle-infrared (2 500 similar to 5 000 nm) wavebands were measured by spectrometers. The spectral characteristics of the flame in air and oxy-combustion atmospheres were analysed. Based on spectral analysis, flame temperature was calculated, and thermal radiation from soot particle and gases in the flame could be quantitively evaluated. The results show that flame temperature in air combustion is lower than in oxy-combustion. Both soot and gas in flames play an important role in thermal radiation in air combustion, and gas is more important for thermal radiation in oxy-combustion. In visible and near-infrared wavebands, the spectral curve shows good continuity in air-combustion due to soot formation, but the radiative spectrum reduces in oxy-combustion. In the mid-infrared waveband, the gas radiation spectrum of air-combustion is obviously weaker than that of oxycombustion.