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An experimental and kinetic modeling study of cyclopentane and dimethyl ether blends
Lokachari, Nitin; Wagnon, Scott W.; Kukkadapu, Goutham; Pitz, William J.; Curran, Henry J.
Cyclopentane is a suitable naphthene, or cycloalkane, in a palette for multi-component gasoline surro- gate fuels due to its presence in market fuels and its relevance to alkyl substituted cyclopentanes also present. However, the previous oxidation studies of cyclopentane have primarily focused on neat mixtures. Blending cyclopentane with dimethyl ether in this work therefore serves to inform our understanding of, and improve predictive models for, multi-component mixtures. In this work, the auto-ignition of cyclopentane/dimethyl ether blends was studied in a high-pressure shock tube and in a rapid compression machine. A wide range of temperatures (650 1350 K) and elevated pressures of 20 and 40 bar were studied at equivalence ratios of 0.5, 1.0 and 2.0 in air for two blending ratios (30/70 and 70/30 mole% cyclopentane/di-methyl ether mixtures). A detailed kinetic model for cyclopentane was revised to capture the measured ignition delay times and apparent heat release rates in this study. Literature ignition delay time, jet-stirred reactor, and laminar burning velocity measurements of neat cyclopentane were used as additional validation. Improvements to the kinetic model were based on recent literature studies related to sub-models including cyclopentene and cyclopentadiene which allowed the removal of previous local rate-constant optimizations. Low temperature reactivity of cyclopentane was found to be controlled by the branching ratio between concerted elimination of H ˙O 2 and the strained formation of ˙ Q OOH radicals in agreement with previous studies. In this study, the low branching ratio of ˙ Q OOH formation increases the influence of a competing consumption pathway for cyclopentyl-peroxy (CPT ˙O 2 J) radicals. The sensitivity of the simulated ignition delay times to the formation of cyclopentyl hydroperoxide (CPTO 2 H), from CPT ˙O 2 J and H ˙O 2 , is discussed. The current model is used to analyze the influence of dimethyl ether on the reactivity of cyclopentane in the context of previous literature studies of dimethyl ether binary blends with ethanol and toluene. The authors at NUI Galway recognize funding support from Science Foundation Ireland (SFI) via their Principal Investigator Program through project number 15/IA/3177. Portions of this work were performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52–07NA27344 and were conducted as part of the Co-Optimization of Fuels & Engines (Co-Optima) project sponsored by the DOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies and Vehicle Technologies Offices. The authors from LLNL would also like to thank Dr. Matthew McNenly, Dr. Russell Whitesides, and Dr. Simon Lapointe for access to their computational solvers, tools, and discussion. 2022-11-13
Keyword(s): Cyclopentane; Gasoline surrogates; Chemical kinetics; Shock-tube; Rapid compression machine
Publication Date:
2021
Type: Journal article
Peer-Reviewed: Yes
Language(s): English
Contributor(s): Science Foundation Ireland
Institution: NUI Galway
Publisher(s): Elsevier
File Format(s): application/pdf
First Indexed: 2021-01-22 07:31:55 Last Updated: 2021-01-22 07:31:55