Experimental study of a laminar jet flame interacting with a horizontal wall

The variation of flame property was analyzed by approaching horizontal wall. The effects of horizontal wall approaching vary the flame shape, structure and even the dynamic behavior, including variation of the flame bulge and flame winding as well as flame fluttering. When the wall was moving closer to the flame, the flame bulge near tip changed from triangle-to-tetragonal-shape and became larger in area. Depending on the wall distance, there were two interacting mechanisms influencing each other: buoyancy and the momentum mechanisms. When the distance between the wall and flame was reduced, the distribution area of high-temperature flame zones was increased and the maximum temperature zone was found near the top wall. For OH radical distribution, it depended on the distance between the wall and flame. For pollution emissions, no obvious change on NO_x emission could be found, and CO emission was increased as the horizontal wall moved toward the flame. The existence and approaching of the wall had an apparent and profound influence on the fundamental physical phenomenon and dynamic response of the flame. This is an abstract of a paper presented at the 30th International Symposium on combustion (Chicago, IL 7/25-30/2004).