Axial and radial temperature profiles of the gaseous slab in between two symmetric counterflow premixed flames of methane are measured. The results indicate that for widely separated lean and rich flames, there exists a temperature dip which is accounted for on the basis of radiative heat loss. For lean flames, the dependence of the temperature dip on the flame separation distance, and hence volume of the emitting gas, is determined. The calculated total radiant loss from the transparent gas volume, based on CO2H2O emissivities obtained from Hottel's curves, results in average temperature drops which closely agree with the measured values. The data are also in favorable agreement with the previously developed theory for radiatively cooled counterflow premixed flames. Also reported is the influence of the thermocouple coating thickness on the measured temperatures. Potential application of the present experimental method to the evaluation of effective emissivities of luminous and nonluminous slabs of combustion products of different fuels is discussed.
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Fuel Technology
- Energy Engineering and Power Technology
- General Physics and Astronomy