Flame propagation inhibition study on methane/air explosion using CO2 twin-fluid water mist containing potassium salt additives

In order to improve the explosion suppression efficiency, experiments were conducted on a self-built visual halfopen explosion pipe to study the synergistic explosion inhibition effect of CO2 twin-fluid water mist containing potassium salt additives. Results showed that: the inhibition effect of CO2 twin-fluid water mist with potassium salt additive increased with the spraying time, the peak overpressure and flame speed declined obviously, and the brightness of the flame was lower or even disappeared, indicating the flame propagation was better blocked. Comparing to 5s CO2 twin-fluid water mist, after the addition of 6% K2CO3, the maximum overpressure and flame speed reduced by 28.87% and 15.07% respectively, and the arrival time of the flame to the end of the pipe prolonged by 21.57%. The inhibition order of CO2 twin-fluid water mist containing four potassium salt additives from high to low is K2CO3> K2C2O4> KCl > KH2PO4. The number of flame free radicals O, H, OH in the whole explosion system decreased significantly under the inhibition of CO2 twin-fluid water mist containing potassium salt additive, indicating potassium salt additive and CO2 twin-fluid water mist have a synergistic effect on inhibiting gas explosion, which can enhance the physical and chemical inhibition effect on flame propagation.