Temperatures of flames on porous burners

Experiments have been carried out with a porous flat flame burner, with heat extraction, on hydrogen-oxygen and hydrogen-air flames. The temperatures of these flames were determined experimentally and compared with those calculated from the thermodynamic data and the measured heat loss to the burner. The hydrogen concentration profile through the flames was also determined with a quartz microprobe and a mass spectrometer. It is shown that the difference between experimental and calculated flame temperatures can be reduced to about 20 degC by preventing atmospheric diffusion into the working section of the burner and by taking into account the amount of unburnt hydrogen at the plane of maximum flame temperature.