Study on the Explosion Suppression Characteristics and Mechanism of C ₆ F ₁₂ O on Hydrogen-Doped Natural Gas

Perfluorohexanone (C6F12O), an environmentally friendly chemical suppressant with strong heat absorption and radical scavenging capability, is increasingly recognized as a promising alternative to conventional halogenated inhibitors for explosion mitigation. This study systematically investigates the suppression behavior of C6F12O in hydrogen-doped natural gas mixtures using a closed visual combustion chamber charged with real multi-component natural gas. The effects of suppressant dosage under different hydrogen fractions are quantified, and the associated chemical mechanisms are analyzed using the Chemkin platform. High-speed imaging shows that C6F12O injection disrupts flame-front continuity and alters flame propagation morphology, thereby inhibiting sustained flame expansion. Experimental results indicate that, perfluorohexanone exhibits a significant non-linear dose–response characteristic on the explosion of hydrogen-blended natural gas: under low and medium hydrogen blending conditions, the explosion suppression efficiency increases with the rise of perfluorohexanone dosage, where 30 g of perfluorohexanone can achieve a 13.7% reduction in the peak explosion overpressure of the pure natural gas system; a clear safety dose threshold exists under high hydrogen blending conditions, where a dosage of 10 g perfluorohexanone delivers a 19.2% reduction in peak overpressure, while an excessive dosage above 40 g will lead to the weakening or even reversal of the explosion suppression effect. Chemical kinetic analysis reveals that C6F12O suppresses hydrogen-doped Natural gas explosions primarily by enhancing chain-termination reactions while weakening chain-branching pathways. Key elementary reactions, including R1021 (CF3+H≤>CF2+HF) and R1123 (CF2:O+H≤>CF:O+HF), contribute most significantly to flame inhibition. These findings provide quantitative guidance for safety assessment of hydrogen-enriched natural gas systems and for optimizing C6F12O-based explosion suppression strategies.