High-pressure shock tube study of ethanol oxidation: Ignition delay time and CO time-history measurements
Journal Article
·
· Combustion and Flame
- Univ. of Central Florida, Orlando, FL (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Argonne National Lab. (ANL), Argonne, IL (United States)
Ethanol oxidation was studied by measuring CO time-histories and ignition delay times behind reflected shockwaves at elevated pressures. In this study, experimental conditions included a temperature range of 960–1580 K, pressure range of 17.8–23.9 atm, and initial fuel concentrations of 6.54% and 0.25% with nitrogen and argon used as bath gasses, respectively. The equivalence ratio for high fuel loading was kept constant at 1.0, and for low fuel loading equivalence ratios were 1.0 and 0.5. For high fuel loading, early heat/energy release was observed in nearly all ignition delay time measurements, indicative of preignition; however, data collected are in good agreement with model predictions. These events are interpreted as a transition from mild to strong ignition. For the low fuel loading cases (Φ = 1.0 and 0.5), no early heat/energy release was observed. Comparisons of measured CO concentration profiles with the predictions from kinetic mechanisms of Metcalfe et al. (2013), Mittal et al. (2014), and Zhang et al. (2018) were made assuming constant internal energy and volume for the test gas. Such comparisons in addition with performed sensitivity and pathway analyses for CO formation revealed lower temperature sensitivity to the bimolecular reaction of methyl and hydroperoxyl radicals given by CH3 + HO2CH3O + OH, and H-atom abstraction by the hydroperoxyl radical at the alpha site on ethanol given by elementary reaction C2H5OH + HO2=sC2H4OH + H2O2. Furthermore, the current study provides important validation targets for ethanol chemical kinetic mechanisms and highlights the benefits of time-history measurements at various temperatures and pressures in a shock tube, which are scare in the literature.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Univ. of Central Florida, Orlando, FL (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Science (SC)
- Grant/Contract Number:
- AC02-06CH11357; AC52-07NA27344; EE0007982
- OSTI ID:
- 1580016
- Alternate ID(s):
- OSTI ID: 1763379
OSTI ID: 1644296
OSTI ID: 1576655
- Report Number(s):
- LLNL-JRNL--795653; 989388
- Journal Information:
- Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: C Vol. 212; ISSN 0010-2180
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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OSTI ID:1976997