High Temporal–spatial Distribution of Soot Temperature and Volume Fraction in Single Coal Combustion Flame

Abstract

ABSTRACT In this study, a high-speed imaging technique for recording spectral radiative images at high temporal–spatial resolutions were proposed to visualize the combustion process of a single coal particle. A Shenhua (SH) single coal particle was burned on a McKenna flat-flame burner, and its combustion process was recorded using a high-speed imaging system. The radiative images of the SH single coal particle captured by the imaging system indicated that the particle mainly experienced the release and combustion of volatiles during the luminescence combustion process (lasting more than 62.5 ms). In addition, spectral radiative intensity images at 604 and 808 nm were also obtained from the radiative images, which were shown to enable the calculation of soot temperature and concentration. Thereafter, the temporal and spatial evolution of the soot temperature and volume fraction in the envelope flame of a single coal particle were obtained from the two spectral radiative intensity images. The results revealed that the soot in the single coal flame experienced a temperature increase in the initial stage, and then remained at a high temperature. A large amount of soot was produced in the middle stage of combustion, whereas small amounts of soot were produced in the initial and later stages.