Influence on fluorocarbons flammability limits in the mixtures of H2-N2O and CH4-N2O

Abstract

The flammability limits for combustible gas (methane, hydrogen)-nitrous oxide-fluorinated hydrocarbon (trifluoromethane CHF3, pentafluoroethane C2HF5, perfluorobutane C4F10) mixtures are experimentally determined. The upper and lower flammability limits turned out to be, respectively, significantly higher and lower as compared to those characteristic of the combustion in air. The compositions of the mixtures at the peaks of the flammability curves are characterized by lower values of the fuel equivalence ratio φ (in most cases, φ < 0.1) as compared to the combustion in air and in a 25 vol % oxygen-nitrogen medium (typically φ > 0.5). It was established that the inhibiting concentrations of fluorinated hydrocarbons for the combustion of methane and hydrogen in nitrous oxide are similar, in contrast to the combustion in oxygen- nitrogen oxidative media. A qualitative interpretation of the results is given.