Dependence of Biofuel Ignition Chemistry on OH-Initiated Branching Fractions

Abstraction of hydrogen by ȮH is the dominant initiation step in low-temperature oxidation biofuels. Theoretical chemical kinetics calculations for such reactions provide a direct means quantifying rates abstraction, which are critical to modeling biofuel combustion. However, several cases and despite agreement on total rate coefficients, branching fractions (i.e. distribution initial radicals) can vary depending level theory, leads variations ignition delay time predictions. To examine connection between predictions, simulations were conducted 1-butanol, cyclopentanone, methyl propanoate at 10 atm from 500–1000 K. For each case, utilized recent combustion mechanisms produce an set trends. H-abstraction then replaced using literature effects ȮH-initiated chemistry. Branching found significantly influence chemistry, specifically case even when coefficients relatively consistent. From comparison site-specific literature, 1-butanol not consistent, resulted times differing factors up 6.3 1.2 respectively. Conversely, both agree, unaffected. observed dependence fractions, intermediate development necessary validate ensure accurate model Speciation measurements one example that link radical-specific, fundamental pathways determine fractions.