Active suppression of premixed methane/air explosion propagation by non-premixed suppressant with nitrogen and ABC powder in a semi-confined duct

A semi-confined duct with an explosion suppression device was designed to investigate experimentally the active explosion suppression by non-premixed nitrogen and ABC powder for a premixed methane/air mixture. The duct was 20 m long with cross-sectional area of 0.08 m x 0.08 m. The results show that the total time from accepting flame signal to forming jet curtain barrier is about 117 ms, and the time from accepting flame signal to depositing ABC powder is 919 ms. The flame-arrival time differences between a flame transducer in front of spurting suppressant position and the triggering flame transducer in the suppression experiments are all between 117 ms and 919 ms, which indicates that the active explosion suppressions by spurting ordinary and superfine ABC powders are both successful. Spurting nitrogen and ABC powder has an obvious suppression effect on the explosion overpressure and the flame propagation speed. The maximum overpressure and the flame propagation speed at each point for spurting superfine ABC powder are both almost smaller than that of ordinary ABC powder. It indicates that the suppression effect of spurting superfine ABC powder and nitrogen was more apparent than that of ordinary ABC powder and nitrogen. After the first gas explosion propagation is controlled successfully, the multiple explosions propagation can still be suppressed absolutely by the surplus ABC powder and nitrogen. Research results will provide a new method for the suppressions of gas explosions in mine roadways and gas transmission pipelines. (C) 2016 Elsevier B.V. All rights reserved.