Measurement of Flame Temperature by Spectral Reversal Method Using Photography

• Published in: Proceedings of the Physico-Mathematical Society of Japan. 3rd Series Vol. 23; pp. 646 - 663
• Main Authors: KINOSITA, Koreo, ARITA, Kenzi
• Format: Journal Article
• Language: English
• Published: THE PHYSICAL SOCIETY OF JAPAN , The Mathematical Society of Japan 1941
• ISSN: 0370-1239; 2185-2707
• DOI: 10.11429/ppmsj1919.23.0_646

The spectral reversal method is considered to be the most precise method for the measurement of flame temperature. In order to establish a method to determine the reversal temperature more accurately, we tried the application of photographic observations to the judgement of reversal. Determination of the reversal temperature with far better precision than by the visual method was not realized unfortunately, owing to the fluctuation of the temperature of the flame which was unavoidable even when the air and the gas pressure were kept carefully constant. But the following results were obtained, and the complicated nature of the reversal phenomenon was revealed. (1) The spectral lines of metal vapour in the flame are not narrow sharp lines, but they have broad width of the order of 0•5-1.5Å (at one thousand and several hundred degrees). Especially, the intensity distribution curve of an emission line shows a conspicuous indent at the middle, due to the self-absorption of the outermost cooler layer of the flame. (2) Visual reversal method is likely to give a little lower temperature than that of the inner hotter part of the flame, according to the self-absorption effect. (3) The temperature of the inner hotter part of the flame can be estimated by the photographic method; i.e. when the protuberances on the both sides of the indent in the microphotometric trace of the line just appear, the temperature of the black radiation from behind the flame is equal to that of the inner hotter part of the flame. (4) A very accurate measurement will be realized by this method, in the case of a thoroughly stationary flame. The photographic method will be suitable for the investigation of the mean temperature of the instantaneous combustions or explosions repeated periodically, as in the internal combustion engines