Chemistry of molecular growth processes in flames.

Chemical mechanisms of pyrolysis, growth, and oxidation processes in flames have traditionally been inferred from spatial profile measurements of species concentrations. Experimental investigations now include the detection of numerous minor species such as reactive radicals and intermediate hydrocarbons. In assessing a proposed mechanism important new constraints can be established when the detailed species profile data are combined with velocity and temperature measurements and analyzed to determine production and destruction rates for specific molecules. Recent results on hydrocarbon diffusion flames provide new information on the interplay between chemical and transport processes. These measurements have led to direct tests of proposed routes for the formation of aromatic hydrocarbons and the first, small soot particles. The inception chemistry of hydrocarbon growth reactions and initial particle formation is thought to control soot formation, flame radiation and energy transfer, and pollutant emission in combustion environments.