Temperatures of positively and negatively stretched flames

Both tubular flame temperature and Bunsen flame temperature have been measured for lean methane, hydrogen and propane/air mixtures. These temperatures have been compared with the adiabatic flame temperature, which is the typical temperature with no stretch. Results show that, the temperature of the tubular flame is almost the same as the adiabatic flame temperature for a lean methane/air mixture, considerably higher for a lean hydrogen/air mixture, and lower for a,lean propane/air mixture. For the temperature around the Bunsen flame tip, this response is opposite to that of the tubular flame. To examine radiation effect, numerical simulation has been conducted. It is found that the radiative heat loss only reduces the flame temperature by 30 to 80degreesC. Thus, the different dependency of flame temperature on the mixtures is explained by stretch effect with the Lewis number considerations, and the response of these flames exhibits opposite behavior.