Experimental and kinetic modeling study of the low-temperature and high-pressure combustion chemistry of straight chain pentanol isomers: 1-, 2-and 3-Pentanol

Pentanols have received significant attention as a potential alternative fuel or fuel additive owing to their high energy densities and low vapor pressure. The development of robust chemical kinetic models for al-ternative fuels which can provide accurate and efficient predictions of combustion performance across a wide range of engine relevant conditions is important in developing cleaner, more efficient combustors. Al-though the high temperature oxidation kinetics of pentanol isomers has been researched considerably, their low temperature combustion chemistry needs further investigation. While previously proposed low tempera -ture mechanisms for 1-pentanol based on analogy and rate rules need further refinement, the low temperature oxidation kinetics of 2-pentanol and 3-pentanol has not been studied previously by any means, experimen-tally or theoretically. A newly developed kinetic mechanism is presented in this work for the three straight chain pentanol isomers: 1-, 2-and 3-pentanol. Low temperature kinetics is based on a recent study by Lock-wood et al., 2022 [20] involving theoretical calculations at the CCSD(T)/cc-pV & INFIN; Z level of theory for the oxidation pathways involving alcohol peroxy radicals. Rate of production analyses performed in this study highlight the importance of the newly added pressure-dependent reactions of the & alpha;-alcohol peroxy radical forming an R O2 adduct. While the & alpha;-alcohol fuel radical reacts with O 2 to directly decompose via a chemi-cally activated pathway at low pressures, the formation of the R O2 adduct is favored at high pressures. The detailed model is comprehensively validated against new ignition experiments at low temperature and high pressure, together with the wide range of data available in the literature. Both qualitative and quantitative predictions of the experimental data using the proposed kinetic model are satisfactory for all three pentanol isomers studied here.

Automated summary

The low temperature oxidation kinetics of pentanol isomers, including 1-pentanol, 2-pentanol, and 3-pentanol, have been studied in this research. A newly developed kinetic mechanism based on recent experimental and theoretical calculations accurately predicts the combustion performance of these three pentanol isomers. The comprehensive validation of the proposed kinetic model shows satisfactory qualitative and quantitative predictions when compared to experimental data.