ID#: 140
Abstract Title: Observation of Flame Structure in Low Damkohler Number Fields
Session Title: Premixed Turbulent Flames III
Session Date: 7/31/01
Session Start Time: 8:30 AM
Contributing Author: Fuchihata, M.
Organization: Kinki University
Country: Japan
Authors: Manabu Fuchihata, Tamio Ida, Yukio Mizutani, Masashi Katsuki
Short Abstract: We discussed the flame structure in low Damk–hler number fields. Low Damk–hler number flames were successfully formed, by a neighboring hot burnt gas stream, in a relatively weak turbulence field of a very lean premixture, which gave a sufficiently long chemical characteristic time. Laser tomography, chemiluminescence detectors, LDV and thermocouple were used simultaneously for observing the lean turbulent premixed flames with silica powder seeded. As a result, the transition of flame structure from a distributed reaction zone to a wrinkled laminar flame was observed in detail by traversing the observation point from upstream to downstream. Further, the flame structures, in which a distributed reaction structure coexists with a propagating flame structure, were observed in the transition region. It was concluded that the propagating flame emerged amid the distributed weak reaction region, and the distributed reaction region was divided up by the propagating flame at the moment. When the propagating flame sufficiently grew, it started to propagate into the lean mixture stream and there is seen no pseudo-distributed reaction zone outside the propagating flame, because it is separated from the lean reactant flow by the flame.