کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4764505 | 1423550 | 2018 | 18 صفحه PDF | دانلود رایگان |
This work identifies classes of cool flame intermediates from n-heptane low-temperature oxidation in a jet-stirred reactor (JSR) and a motored cooperative fuel research (CFR) engine. The sampled species from the JSR oxidation of a mixture of n-heptane/O2/Ar (0.01/0.11/0.88) were analyzed using a synchrotron vacuum ultraviolet radiation photoionization (SVUV-PI) time-of-flight molecular-beam mass spectrometer (MBMS) and an atmospheric pressure chemical ionization (APCI) Orbitrap mass spectrometer (OTMS). The OTMS was also used to analyze the sampled species from a CFR engine exhaust. Approximately 70 intermediates were detected by the SVUV-PI-MBMS, and their assigned molecular formulae are in good agreement with those detected by the APCI-OTMS, which has ultra-high mass resolving power and provides an accurate elemental C/H/O composition of the intermediate species. Furthermore, the results show that the species formed during the partial oxidation of n-heptane in the CFR engine are very similar to those produced in an ideal reactor, i.e., a JSR.The products can be classified by species with molecular formulae of C7H14Ox (xâ¯=â¯0-5), C7H12Ox (xâ¯=â¯0-4), C7H10Ox (xâ¯=â¯0-4), CnH2n (nâ¯=â¯2-6), CnH2nâ2 (nâ¯=â¯4-6), CnH2n+2O (nâ¯=â¯1-4), CnH2nO (nâ¯=â¯1-6), CnH2nâ2O (nâ¯=â¯2-6), CnH2nâ4O (nâ¯=â¯4-6), CnH2n+2O2 (nâ¯=â¯0-4, 7), CnH2nO2 (nâ¯=â¯1-6), CnH2nâ2O2 (nâ¯=â¯2-6), CnH2nâ4O2 (nâ¯=â¯4-6), and CnH2nO3 (nâ¯=â¯3-6). The identified intermediate species include alkenes, dienes, aldehyde/keto compounds, olefinic aldehyde/keto compounds, diones, cyclic ethers, peroxides, acids, and alcohols/ethers. Reaction pathways forming these intermediates are proposed and discussed herein. These experimental results are important in the development of more accurate kinetic models for n-heptane and longer-chain alkanes.
Journal: Combustion and Flame - Volume 187, January 2018, Pages 199-216