Fuel Preheat Effects on Soot Formation in Soot-Emitting Laminar Microgravity Jet Diffusion Flames

Abstract

Abstract An experimental investigation conducted at the 2.2s drop tower of the NASA Lewis Research Center is presented to quantify the influence of moderate fuel preheat on soot formation within 0-g laminar gas jet diffusion flames. The experimental methodology implements jet diffusion flames of nitrogen-diluted acetylene fuel burning in quiescent air at atmospheric pressure. Fuel preheat in the 0-g laminar jet diffusion flames is found to reduce soot loadings on the annular region but causes an increase in soot volume fractions on the centerline. In addition, fuel preheat reduces the spatial extent of the soot field in 0-g. The results also show that the soot growth stage is shortened when elevated fuel temperatures are used. Finally, an attempt is made to provide an explanation for the pronounced annular character of the soot field in 0-g.