Effects of hydrogen and helium addition to fuel on soot formation in an axisymmetric coflow laminar methane-air diffusion flame

摘要

In this work the influence of hydrogen addition to fuel on soot formation in a laminar coflow methane/air diffusion flame is investigated both experimentally and numerically. In particular, soot volume fraction and soot temperature field measurements were performed in a coflow laminar methane diffusion flame with and without hydrogen and helium addition. Numerically, the governing equations in axisymmetric cylindrical coordinates were solved using the finite volume method. To unambiguously show the different influence of hydrogen addition to methane and ethylene on soot formation relative to that of helium, the identical gaseous reaction mechanism and soot model to those employed previously by Guo et al. were used. A comparison between the present experimental and numerical soot volume fraction also provides direct evidence on how the soot model used by Guo et al. to the C2H4 diffusion flame performs when applied to the methane flame investigated here, i.e., the generality of the soot model.