Citation

Li J, Pan J, Li J. Fire Safety J. 2022; 133: e103665.

Copyright

(Copyright © 2022, Elsevier Publishing)

DOI

10.1016/j.firesaf.2022.103665

PMID

unavailable

Abstract

The dominant combustion mode in underground coal fires (UCFs) is smouldering. A packed coal bed reactor with natural convection as the driving force was designed to represent the spatial features of three typical UCFs. Effects of air leakage through the left-hand wall and the burning position were investigated with three experimental cases. The ignition test showed that coarser particles (0.5-1 mm) failed to be ignited, while self-sustained smouldering was successfully initiated for finer particles (<0.5 mm). The repeatability test yielded reproducible results at a macroscopic level (maximum difference of 6.4%), with main uncertainties coming from the ignition stage when the formation of cracks introduces randomness. It was observed that air leakage through the left-hand wall enhanced the smouldering temperature near the wall boundary, and the enhancement became more prominent with the increasing depth. When ignition was initiated at the middle part of the reactor, the top region of the coal bed burned nearly twice faster. The quantitative results are dependent on specific conditions in the present study, while the relative differences among three cases could shed some light on smouldering propagation in actual UCFs from the perspective of fire safety.

Language: en

Keywords

Air leakage; Burning position; Coal; Packed bed; Smouldering combustion; Underground coal fires