Yield Sooting Index (YSI)

Yield Sooting Index (YSI) is a property we have defined and measured for hundreds of hydrocarbons.  It characterizes the influence of molecular structure on soot formation rates in combustion devices.


Soot refers to carbonaceous particles that are often produced in combustion devices and emitted as air pollution.  Recent studies show that the current concentrations of soot in the atmosphere make it the second most important source of global warming, with a total radiative forcing that is about two-thirds that of carbon dioxide.  Soot emissions constitute roughly 10% of the ambient fine particulate matter that is estimated to kill over 3 million people worldwide each year.  Soot is the main actor in toxic emissions from cookstoves that kill over 3 million people annually in developing countries.
Soot formation rates depend strongly on the molecular structure of the fuel.  For example, the photo compares pool fires of ethanol (left) and benzene (right); although the flames have similar sizes and shapes, the benzene flame produces vastly more soot.  This dependence means that ongoing changes in fuel composition due to concerns over energy security and renewability will change soot emissions.  The information provided by YSI’s is needed to intelligently manage these fuel transitions so that they reduce soot emissions and their environmental consequences.


YSI publications from our group

  • Montgomery, M. J.; Das, D. D.; McEnally, C. S.; Pfefferle, L. D. Analyzing the robustness of the yield sooting index as a measure of sooting tendency. Proc. Combust. Inst.2018. DOI: 10.1016/j.proci.2018.06.105

  • McEnally, C. S.; Xuan, Y.; St. John, P. C.; Das, D. D.; Jain, A.; Kim, S.; Kwan, T. A.; Tan, L. K.; Zhu, J.; Pfefferle, L. D. Sooting tendencies of co-optima test gasolines and their surrogates. Proc. Combust. Inst.2018. DOI: doi.org/10.1016/j.proci.2018.05.071

  • D.D. Das, C.S. McEnally, T.A. Kwan, J.B. Zimmerman, W.J. Cannella, C.J. Mueller, L.D. Pfefferle, Sooting tendencies of diesel fuels, jet fuels, and their surrogates in diffusion flames, Fuel, 197 (2017) 445-458.DOI:10.1016/j.fuel.2017.01.099

  • D.D. Das, W.J. Cannella, C.S. McEnally, C.J. Mueller, L.D. Pfefferle, Two-dimensional soot volume fraction measurements in flames doped with large hydrocarbons, Proc. Comb. Inst. 36 (2017) 871-879. DOI:10.1016/j.proci.2016.06.047

YSI publications of fuels from other collaborators

  • Ryan, C. F.; Moore, C. M.; Leal, J. H.; Semelsberger, T. A.; Banh, J. K.; Zhu, J.; McEnally, C. S.; Pfefferle, L. D.; Sutton, A. D., Sustainable Energy & Fuels, 2020, 4 (3), 1088-1092. DOI: 10.1039/c9se01014a

  • Huq, N. A.; Huo, X.; Hafenstine, G. R.; Tifft, S. M.; Stunkel, J.; Christensen, E. D.; Fioroni, G. M.; Fouts, L.; McCormick, R. L.; Cherry, P. A.; McEnally, C. S.; Pfefferle, L. D.; Wiatrowski, M. R.; Benavides, P. T.; Biddy, M. J.; Connatser, R. M.; Kass, M. D.; Alleman, T. L.; St John, P. C.; Kim, S.; Vardon, D. R., Proc Natl Acad Sci, 2019DOI: 10.1073/pnas.1911107116

  • O. Staples, J. H. Leal, P. A. Cherry, C. S. McEnally, L. D. Pfefferle, T. A. Semelsberger, A. D. Sutton and C. M. Moore, Energy & Fuels2019DOI: 10.1021/acs.energyfuels.9b02557.

  • X. Huo, N. A. Huq, J. Stunkel, N. S. Cleveland, A. K. Starace, A. E. Settle, A. M. York, R. S. Nelson, D. G. Brandner, L. Fouts, P. C. St. John, E. D. Christensen, J. Luecke, J. H. Mack, C. S. McEnally, P. A. Cherry, L. D. Pfefferle, T. J. Strathmann, D. Salvachúa, S. Kim, R. L. McCormick, G. T. Beckham and D. R. Vardon, Green Chemistry2019DOI: 10.1039/C9GC01820D.

YSI-related publications from other research groups

  • M. Kashif, P. Guibert, J. Bonnety, G. Legros. “Sooting tendencies of primary reference fuels in atmospheric laminar diffusion flames burning into vitiated air.” Comb. and Flame 161 (2014) 1575-1586.  doi:10.1016/j.combustflame.2013.12.009
  • M. Kashif, J. Bonnety, A. Matynia, P. Da Costa, G. Legros. “Sooting tendencies of some gasoline surrogate fuels: combined effects of fuel blending and air vitiation.” Comb. and Flame (in press).  doi:10.1016/j.combustflame.2014.12.005
  • Y. Xuan, G. Blanquart. “Numerical modeling of sooting tendencies in a laminar co-flow diffusion flame.” Comb. and Flame 160 (2013) 1657-1666.  doi:10.1016/j.combustflame.2013.03.034