Measurement of the temperatures of stationary flames

Abstract

The concept of temperature as applied to flames is discussed. A number of proposed methods for measuring the temperatures of flames are critically reviewed and the optical method of Kurlbaum-Fery is described and examined in detail. This method depends upon comparing the brightness temperature of a continuous radiator with the brightness of the radiation from the flame colored with an alkali-metal vapor at a given spectral line. From a consideration of the laws of radiation it is shown that the true flame temperature is equal to the brightness temperature of the comparison radiator, as read with an optical pyrometer, when the spectral line is just reversed as seen in a spectrometer.

Curves representing flame temperature as a function of air-gas ratio as measured by the line-reversal method are given for Pittsburgh natural gas, methane, propane, and carbon monoxide. These results are compared with measurements depending on the flame gases heating a solid radiator contained in the flame and with the calculated results for the maximum temperature attainable at complete combustion.