Soot evolution in turbulent nonpremixed ethylene/hydrogen bluff body flames

Sili Deng, Michael E. Mueller, Qing N. Chan, Nadar H. Qamar, Bassam B. Dally, Zeyad T. Alwahabi, Graham J. Nathan

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The evolution of soot in a turbulent nonpremixed bluff body ethylene/hydrogen (2:1 by volume) flame was investigated using a combination of experiments and Large Eddy Simulation and compared with a neat ethylene counterpart [Mueller et al., Combust. Flame, 160, 2013]. The maximum soot volume fractions in the recirculation zone and jet-like region of the ethylene/hydrogen case are significantly lower than that of the ethylene case. Flamelet calculations demonstrated that hydrogen addition suppressed soot formation due to the reduction of the C/H ratio, resulting in an estimated fourfold reduction in soot volume fraction due to chemical effects. Soot reduction in the downstream jet-like region of the flame is quantitatively consistent with this chemical effect. However, soot reduction in the recirculation zone is substantially larger than this analysis suggests, indicating an additional hydrodynamic effect. Large Eddy Simulation was used to further investigate soot evolution in the recirculation zone and to elucidate the role of hydrogen addition. For the same jet Reynolds number as the neat ethylene case (~ 30,900), the addition of hydrogen requires a higher jet velocity, and this leads to a leaner recirculation zone that inhibits soot formation and promotes soot oxidation.
Original languageEnglish (US)
Title of host publication2016 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2016
PublisherEastern States Section of the Combustion Institute
StatePublished - Jan 1 2016
Externally publishedYes


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