Extinction and structure of ultra lean premixed flame formed in opposite flow has been studied experimentally. Two different concentration mixtures, extremely lean premixed gas and lean premixed gas, impinged on each other. The bulk stretch rate were varied from 80-s to 270-s, and the Lewis number (Le) were varied from 0.99 to 1.85. The local stretch rate due to flow divergence and the stagnation point were estimated by measuring the centerline velocity profile with LDV and the reaction zone was identified by OH profiles using PLIF (Planar Laser-Induced Fluorescence). The extinction behavior depends on the mixture property and the flow strain rate. For small strain rate and Le>1, the extinction limit is nearly constant regardless'of super lean premixed gas condition. On the other hand, for Le<1 and the strain rate large, ultra lean premixed gas interacts with lean premixed gas and the stable region extends to the lower fuel concentration zone.
|ジャーナル||Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B|
|出版ステータス||Published - 1999|
ASJC Scopus subject areas