Influence of ignition delay on explosion severities of the methane-coal particle hybrid mixture at elevated injection pressures

This work investigated the influence of particle-injection pressure and ignition delay on explosion parameters of methane-coal particle mixture using a 20-L sphere. Results indicated that the maximal explosion pressure P-max and the maximal pressure rise rate (dP/dt)(max) tended to first increase and then decrease, with ignition delay increasing as the particle-injection pressure ranged from 1.2 to 2.4 MPa, attaining their maximum values at different moments. However, as the particle-injection pressure reached 3 MPa, P-max and (dP/dt)(max) displayed a downtrend with an increase in ignition delay. Furthermore, a 3D CFD model was developed to evaluate the turbulent flow field and the gas-solid particle interaction within the tank. Results demonstrated four continuous stages for transient movement of coal particles. Under various particle-injection pressures, the time for particle dispersion stabilization differed significantly. These results can potentially contribute to the prevention of methane-coal particle explosions. (C) 2020 Elsevier B.V. All rights reserved.