Explosion and explosion suppression of gas/deposited coal dust in a realistic environment

Abstract

Gas/deposited coal dust explosions are always one of the major accidents in coal mines. In this paper, gas/deposited coal dust explosion and explosion suppression experiments are conducted in a large tunnel to clarify the propagation law of gas/deposited coal dust explosion and the effect of ultra-fine dry powder on it in a real environment, and the evaluation method for the explosion wave energy in the roadway is also listed, which provides new ideas for the analysis of explosion accidents in the roadway. The results show that the pressure propagation velocity is always faster than the flame propagation velocity and the initial state of gas accumulation mainly influences the initial explosion propagation process. The increasing concentration of coal dust increases the flame propagation velocity. The maximum explosion (without explosion suppression) is achieved in the 100–120 m range. After the initial accumulation of gas has exploded, the explosion wave energy gradually increases, but the growth rate is slow. After 40 m, as the amount of deposited coal dust raised to participate in the explosion reaction increases, the growth rate of the explosion wave energy accelerates, and after 80 m, the explosion wave energy increases sharply, and then decreases as the fuel is consumed. The growth rate of the explosion wave energy is greatest in the 80–100 position interval. The explosion suppressing powder forms an inert cloud barrier in the cross section of the roadway. This barrier prevents the coal dust from continuing to move to the rear of the roadway, creating a region of high coal dust concentration in front of the barrier, resulting in an early maximum of explosion pressure and flame propagation velocity in this region. When the explosion flame passes through the explosion-suppressing cloud barrier, it is suppressed by a combination of surface cooling, gas-phase inerting and dilution, chemical synergy and physical isolation mechanisms.