H. L. Xu, X. S. Wang, R. Gu and H. P. Zhang (2012) Experimental Study on Characteristics of Methane-Coal-Dust Mixture Explosion and Its Mitigation by Ultra-Fine Water Mist. Journal/Journal Of Engineering for Gas Turbines And Power-Transactions Of the Asme 134 6. [In English]
Web link: http://dx.doi.org/10.1115/1.4005816
Keywords: explosion, methane, coal dust, explosion mitigation, water mist, GAS-EXPLOSIONS, DIFFUSION FLAME, POOL FIRE, SUPPRESSION, SPRAYS, EXTINCTION, CLOUDS, TESTS
Abstract: This paper presents the results of an experimental investigation on the characteristics of methane-coal-dust mixture explosion and its mitigation by ultra-fine water mist. Four E12-1-K-type fast response thermocouples, two printed circuit board (PCB) piezotronic pressure transducers were used to obtain the temperature and pressure history, while a GigaView high-speed camera was used to visualize the processes. Different methane concentrations, coal-dust concentrations, diameters of coal particles, and volumes of ultrafine water mist were considered to investigate their effects on methane-coal-dust mixture explosion. The temperature of explosion flame, the maximum explosion overpressure, the maximum rate of overpressure rise, and the critical volume flux of ultra-fine water mist were experimentally determined. The results show that the characteristics of the methane-coal-dust mixture explosion and the mitigating effectiveness by ultra-fine water mist are influenced by the methane concentration, the coal-dust concentration, the coal-dust diameter and the applied volume flux of ultra-fine water mist. For example, both the maximum explosion overpressure and rate of overpressure rise increased with increasing of coal-dust concentrations and methane concentrations. All of the test cases indicate that ultra-fine water mist can mitigate the mixture explosion and suppress the flame propagation efficiently from the images recorded by the high-speed video camera.