Experimental study on the coupling effect of heptafluoropropane and different arrangement of obstacles on methane-air explosion

The influence of heptafluoropropane（CF₃CHFCF₃） with different barrier arrangements on the prevention of methane-air explosions in semi-closed pipes is examined in this research. Using high-speed photography and pressure sensors, the propagation traits and pressure data of flames were captured on the self-built explosion test platform. The findings demonstrate that, in the absence of barriers, a 1% concentration of CF₃CHFCF₃ promotes the spread of methane explosions, with an 8.6% reduces in flame propagation time. However, as CF₃CHFCF₃ concentration rises, the strength of the inhibition of methane explosions weakens with increasing concentration, and at a concentration of CF₃CHFCF₃ greater than 5%, the explosions are completely inhibited. When barriers of different arrangements are introduced, the inhibition impact of CF₃CHFCF₃ on methane explosion is improved. In these barriers, the maximum boosting rate and peak explosion overpressure are decreased by 28.81% and 97.27%, respectively. The staggered arrangement of barriers provides a higher coupling effect when the concentration of CF₃CHFCF₃ is between 1% and 3%, while the symmetrical arrangement of barriers has the optimum coupling effect when the concentration is between 4% and 5%.