Experimental and theoretical study on the suppression effect of CF₃CHFCF₃ (FM-200) on hydrogen-air explosion

This study experimentally and numerically determined the effect of FM-200 on H₂/air explosion. Firstly, the explosion pressure was investigated to evaluate the suppression efficiency. The results indicated that the effect of FM-200 on H₂/air explosion was quite different for various equivalence ratios. FM-200 could enhance the explosion at lean mixture, but suppress the explosion at rich mixture. Then, the burning velocity, heat production and temperature free radicals were investigated. The results also demonstrated that FM-200 exhibited stronger suppression effect in rich explosion. In addition, the increase of free radicals indicated the enhancement effect of FM-200 at lean explosion. Last, the analysis of sensitivity and reaction path was performed to understand the suppression kinetics. It was shown that R1466 and R1468 could suppress explosion at Φ = 1.3 and 1.6, however, they changed into promoting explosion at Φ = 0.8 and 1.0. Moreover, the reaction path analysis indicated that CHF:CF₂→CHF:O→CO could enhance explosion at Φ = 0.8. For CHF:CF₂→CH₂F→HF, it played an important role in scavenging H to suppress explosion at Φ = 1.6. Furthermore, it was indicated that there was a competition between the enhancement and suppression effect at Φ = 1.3.