On the structure, stabilization, and dual response of flat-burner flames

A comprehensive computational and experimental study has been conducted on the structure and stabilization dynamics of the classical planar flame over a flat, porous burner. The specific issue addressed is the apparent dual response nature of the flat-burner flames in that previous studies have shown the existence of two flame speeds for either a given heat loss rate or a given flame standoff distance. The present study demonstrates that the flame response is actually unique when the flame burning rate is considered to be the independent variable, that the turning point behavior of the flame response is a manifestation of system nonmonotonicity rather than extinction, and that the flat-burner flame does not appear to possess distinct extinction states. Results obtained from computational simulation of the flame structure with detailed transport and chemistry agree well with the experimental temperature and major species profiles determined through laser Raman spectroscopy.