The influence of fluorinated hydrocarbons on the combustion of gaseous mixtures in a closed vessel

The influence of various fluorinated inhibitors (CF3H, C2F5H, C3F7H, C3F6H2, CF2ClH, C2F5Cl, C2F5I, C4F8, C4F10, C2F4Br2) on the combustion characteristics of mixtures of hydrogen and air and also of methane and air in a closed vessel has been investigated experimentally. The flammability limits, maximum explosion pressure, and maximum rate of explosion pressure rise have been determined. In some cases, flames of lean mixtures of H-2 or CH4, with air can be promoted by adding fluorinated hydrocarbons. Thus the maximum explosion pressure, Delta P-max, and the maximum rate of pressure rise, (dP/dt)(max), during the explosion of lean mixtures were both elevated by small additions (several vol. %) of fluorinated hydrocarbons; this is caused by heat release during the chemical conversion of the inhibitors. This heat release is high enough to increase Delta P-max and (dP/dt)(max) by 50-100% above the values for mixtures without inhibitors. (C) 2000 by The Combustion Institute.