Ignition characteristics of 2-methyltetrahydrofuran: An experimental and kinetic study

Abstract

The present paper elucidates oxidation behavior of 2-methyltetrahydrofuran (2-MTHF), a novel second-generation biofuel. New experimental data sets for 2-MTHF including ignition delay time measurements in two different combustion reactors, i.e. rapid compression machine and high-pressure shock tube, are presented. Measurements for 2-MTHF/oxidizer/diluent mixtures were performed in the temperature range of 639 − 1413 K, at pressures of 10, 20, and 40 bar, and at three different equivalence ratios of 0.5, 1.0, and 2.0. A detailed chemical kinetic model describing both low-and high-temperature chemistry of 2-MTHF was developed and validated against new ignition delay measurements and already existing flame species profiles and ignition delay measurements. The mechanism provides satisfactory agreement with the experimental data. For identifying key reactions at various combustion conditions and to attain a better understanding of the combustion behavior, reaction path and sensitivity analyses were performed.

A model of tetrahydrofuran low-temperature oxidation based on theoretically calculated rate constants

“…In the case of the addition of tetrahydrofuranyl radical with the radical carbon adjacent to the oxygen atom, the rate constant was reduced by a factor of 3. This is in line with the work of Tripathi et al about the oxidation of 2-methylTHF [11] considering that formed adducts are less stable due to the weak bonding at these sites. The rate parameters of the subsequent reactions, 36-46, and 49-57, were calculated in this work.…”

“…For H-atom abstraction by H-atoms and CH3 and HO2 radicals (reactions 98-103 and 104-116), the rate parameters were calculated in the present work. For H-atom abstractions by OH radical (reactions 104 and 117), they were taken from the study on 2-methylTHF from Tripathi et al [11]. The resulting radicals, bicy(O)(CCJOCC) and bicy(O)(CCJCOC) radicals, are assumed to decompose rapidly to give oxirane and ketenyl radicals and acrolein and HCO radicals, respectively.…”

“…These reactions are known to have an impact on the overall reactivity of the oxidation system in the low-temperature range [33]. The rate parameters for reactions 118-135 were taken from the work of Tripathi et al [11], while those of reactions 136-137 were calculated in this study. The species formed in the previously described reactions can also react in the low to intermediate temperature range, and recent updates in their oxidation under these temperature conditions were included in the mechanism.…”

“…Fenard et al [10] presented a model of the lowtemperature oxidation of 2-methyltetrahydrofuran validated using ignition delay times and mole fraction profiles obtained in a rapid-compression machine. Tripathi et al [11] also developed a model of the lowtemperature oxidation of 2-methyltetrahydrofuran. This model was validated using ignition delay times from both a rapid-compression machine and a high-pressure shock tube.…”

Oxidation of 2-methylfuran and 2-methylfuran/n-heptane blends: An experimental and modeling study

“…The base mechanism has been extensively validated [62][63][64] and contains the relevant chemistry needed to describe the oxidation of C 0 -C 4 species. A sub-model of n-heptane, along with the C 5 and C 6 chemistry, was taken from the most recent optimized dodecane model of Cai et al [65].…”