Impact of suspended coal dusts on methane deflagration properties in a large‐scale straight duct

Abstract

Knowledge about flame deflagrations in mixtures of methane and diluted coal dust assists in the prediction of fires and explosions, and in the design of adequate protective systems. This vital lack of information on the role of hybrid mixtures (methane/coal dust) is covered in this work by employing a novel Large-Scale Straight Duct (LSSD) designed specifically for this purpose. The hybrid fuel was injected along the first 8m of the 30m long LSSD. The results revealed that a 30gm coal dust concentration boosted the flame travel distance, from 6.5m to 28.5m, and increased the over pressure rise profile to 0.135bar. The over pressure rise (OPR), pressure wave velocity, flame intensity and the flame velocity were significantly boosted along the LSSD in the presence of 10gm or 30gm coal dust concentrations in the methane flame deflagrations. Finally, the high speed camera showed that the presence of the coal dust enhanced the turbulence in the front flame. Consequently, the pressure wave and flame velocities were both increased when a 10gm coal dust concentration coexisted with a 9.5% methane concentration in the deflagration.

Experimental data revealing explosion characteristics of methane, air, and coal mixtures

“…18,19,21 In addition to the explosion characteristics, the ignitability, ame deagration and propagation properties of methane-air-coal dust mixture were explored. [22][23][24][25][26][27][28] However, little attention has been paid to the effect of coal dust volatility on explosion characteristics of methane-air-coal dust mixtures.…”

Laboratory Scaled Coal Dust Explosions and Physical Test Results for CFD Explosion Models

“…However, the L/D ratio and the initial ignition energy is higher. It must also be highlighted that the coal dust has been initially injected and premixed with the methaneair mixture before the ignition of the combustible solid and gas phases [6][7][8]. Fig.…”

Experimental Analysis on Gas and Solid Residues of Pre- and Post-explosion Coal Dust

“…Bai et al 41 studied the flame properties of coal dust explosion in a large-scale pipeline and reported the flame structure characteristics with three concentric zones and the evolution process of flame structure parameters and propagation velocity with time after coal dust explosion. Ajrash 42 proved that the presence of coal dust will increase the turbulent disturbance of flame and then increase the flame propagation velocity and shock wave pressure in the mixed explosion system of coal dust and methane.…”