Article ID Journal Published Year Pages File Type
588307 Process Safety and Environmental Protection 2014 6 Pages PDF
Abstract

High temperature flame fronts generated in methane–air explosions are one of the major hazards in underground coal mines. However, the distribution laws of the flame region in explosions of this type and the factors influencing such explosions have rarely been studied. In this work, the commercial software package AutoReaGas, a finite-volume computational code for fluid dynamics suitable for gas explosion and blast problems, was used to carry out numerical simulations of a series of methane–air explosion processes for various initial premixed methane–air regions and cross-sectional areas in full-scale coal tunnels. Based on the simulated results and related experiments, the mechanism of flame propagation beyond the initial premixed methane–air region and the main factors influencing the flame region were analyzed. The precursor shock wave and turbulence disturb the initial unburned methane–air mixture and the pure air in front of the flame. The pure air and unburned mixture subsequently move backward along the axial direction and mix partially. The enlargement of the region containing methane induces that the range of the methane–air flame greatly exceeds the initial premixed methane–air region. The flame speed beyond the initial region is nonzero but appreciably lower than that in the original premixed methane–air region. The length of the initial premixed methane–air region has substantial influence on the size of the flame region, with the latter increasing exponentially as the former increases. For realistic coal tunnels, the cross-sectional tunnel area is not an important influencing factor in the flame region. These conclusions provide a theoretical framework in which to analyze accident causes and effectively mitigate loss arising from the repetition of similar accidents.

► Flame region greatly exceeds initial premixed methane–air region. ► Flame speed beyond initial premixed methane–air region decreases obviously. ► Length of initial premixed region is a main influencing factor for flame region. ► Length of flame region increases exponentially with initial premixed region. ► It provides a theoretical basis for analysis and prevention of relevant accidents.

Related Topics
Physical Sciences and Engineering Chemical Engineering Chemical Health and Safety
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