Shape and Extinction of Jet Diffusion Microflames: Experimental Observations and a Simple Theory

Abstract

The fuel jet velocity at the extinction limit of a jet diffusion flame can be as large as that at the blowoff limit under microflame conditions, requiring detailed understanding of extinction mechanism. This paper first discusses a simple theory to describe the extinction mechanism of jet diffusion microflame. An activation-energy asymptotics technique is adopted with the use of constant-density approximation to predict the extinction limit. Results of experiments for different burner diameters are then presented to compare theoretical predictions with experimental observations.