Fire Safety Science Digital Archive

Characteristics of the aerodynamic and thermal structures near the leading edge of a stationary diff'usion flame established in a boundary layer were examined by flow visualization and temperature measurements, and the effects of the reverse flow on the flame stabilization and the heat transfer mode were discussed. The aspects of the reverse flow region in front of the leading edge of the stationary flame were found to be similar to that of the spreading flame over a combustible material. A stagnation region was formed just ahead of the leading flame edge, and the gas stream passing through the flame zone was observed to be accelerated rapidly. The reverse flow was ascertained to scarcely affect on the heat transfer from the flame zone to the solid phase ahead of the leading flame edge. A stream in low velocity was observed to pass across the leading flame edge behind the stagnation region, and it was inferred that the reverse flow takes an important role in the stabilization of the flame. Although characteristics of a stationary diffusion flame were examined in this study, obtained knowledge could be adopted into the discussion on the spreading flame over combust ible materials in windy conditions.