Coupling effect of fuel property parameters on gas/coal dust composite explosion

In order to reveal the coupling law of the influencing factors in gas/coal dust composite explosion, experiments were conducted in a 20 L spherical explosion device. Multi-factor and single-factor experimental analyses were conducted on four influencing factors according to explosion parameters, including coal concentration, methane volume fraction, coal particle size, and coal type. By conducting orthogonal experiments on the influencing factors, and using the explosion parameters as indicators to carry out range analysis and variance analysis, the influence of each factor on the explosion had been quantified. The experimental results show that the degree of influence of the four factor on pmax are (from strong to weak): methane volume fraction, coal dust mass concentration, coal dust type, and coal dust particle size; the effects on (dp/dt)max are (from strong to weak): methane volume fraction, coal dust mass concentration, coal dust particle size, and coal dust type. For methane concentrations of 9% and 11%, the value of pmax of the composite system decreases with increasing mass of coal dust. When the mass concentration of coal dust increases to 100 g/m3 and 200 g/m3, coupled with 6% volume fraction of methane, it will produce a stronger “incentive” effect, and when the concentration of coal dust is larger, the low volatility will reduce the optimal gas concentration. The existence of a certain critical value of methane concentration will change the influence mode of volatile factors. Below this value, the value of (dp/dt)max of the high volatile coal dust system is higher, and its arrival time is shorter, while above this value, the low volatile fraction system has a higher explosion intensity. Particle size implicates the influence of volatile fraction, the larger the particle diameter, the more obvious the difference produced by the volatile fraction factor. At 11% methane concentration, coal dust with high volatile fraction is more susceptible to the effect of particle size, and the smaller diameter coal dust system has smaller Kst value; at methane concentration close to equivalent, low volatile fraction coal dust is more significantly affected by the particle size factor. © 2022 Explosion and Shock Waves. All rights reserved.