Experimental and numerical analysis of turbulent pulverized coal flame in a coaxial burner

Abstract

A hydrogen supported turbulent pulverized coal combustion flame was investigated experimentally and numerically to analyze combustion characteristics and flame structure. The flame was experimentally investigated by direct measurement methods and non-intrusive optical diagnostic methods. Temperature of gaseous phase was observed by a sheathed thermo-couple, while gas composition was examined by a gas analyzer with a sampling probe. Particle dispersion characteristics and velocity were analyzed by Mie scattering and PIV techniques using an optical measurement system. A numerical analysis was simultaneously performed to investigate the flame in detail by means of LES. The simulation was validated by comparing gaseous temperature, velocity and composition results to the experiment. The issued pulverized coal particles were distributed in limited area even in downstream by forming linear shape of flame. The particles moved by forming a cloud in the flame in upstream, but the cloud was broken up in downstream when it passed the flame surface. The characteristics of particle movement and influence of combustion were discussed with the analyses of particle velocity and momentum transfer. The flame structure was discussed with the results of gaseous mole fraction, and NOx formation was numerically investigated in this study.