Experimental Study on Methane-Coal Dust Mixture Explosion Mitigation by Ultra-Fine Water Mist

This paper presents the results of experimental investigation on methane-coal dust mixture explosion mitigation by ultra-fine water mist. Different concentrations of coal dust, different diameters of coal particles and different volumes of ultra-fine water mist were considered. Their effects on methane-coal dust mixture explosion mitigation are discussed. A GigaView High-speed camera was used to visualize the processes while four E12-1-K type fast response thermocouples and two PCB piezotronic pressure transducers were used to obtain the temperature and pressure history of methane-coal dust mixture explosion mitigated with ultra-fine water mist, respectively. The parameters of the maximum explosion pressure, the maximum rate of pressure rise, and the critical volume flux of explosion mitigation with ultra-fine water mist were determined. The results show that the mitigating efficiency of the methane-coal dust mixture explosion by ultra-fine water mist is mainly influenced by the coal dust concentration, coal dust diameter and application volume flux of ultra-fine water mist, i.e., both the maximum explosion overpressure and the maximum rate of overpressure rise increase with increasing of coal dust concentrations, and the larger the coal dust diameter and applied volume flux of ultra-fine water mist are, the easier the explosion can be mitigated.