Oral presentation given virtually at the ACS Fall 2021 Meeting on August 26 2021.With the growing importance of climate change, soot emissions from engines have been receiving increasing attention since black carbon is the second largest source of global warming. A sooting tendency can be used to quantify the extent of soot formation in a combustion device for a given fuel molecule, and therefore to quantify the soot reduction benefits of alternative fuels. However real fuels are complex

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... s of multiple components. In this work, we have used both experimental and computational methods to investigate how the sooting tendency of a blended fuel mixture is related to the sooting tendencies of the individual components. A test matrix was formulated that includes sixteen mixtures of six components that are representative of the main categories of hydrocarbons in gasoline (n-heptane for alkanes; isooctane for isoalkanes; methylcyclohexane for naphthenes; toluene for aromatics; 1-hexene for olefins; and ethanol for oxygenates). Most of the mixtures contain three to five components. The sooting tendency of each mixture was characterized by yield sooting index (YSI), which is based on the soot yield when a methane/air nonpremixed flame is doped with 1000 ppm of the test fuel. The YSIs were measured experimentally and computed from flame simulations with a detailed kinetic mechanism. The results show that the blending behavior is linear, i.e., the YSI of the mixtures is the mole-fraction-weighted average of the component YSIs. This linear blending rule has been used to accurately predict the YSIs of several real gasolines from their detailed hydrocarbon analyses.