Autoignited and non-autoignited lifted flames of pre-vaporized n-heptane in coflow jets at elevated temperatures

Handle URI:
http://hdl.handle.net/10754/562927
Title:
Autoignited and non-autoignited lifted flames of pre-vaporized n-heptane in coflow jets at elevated temperatures
Authors:
Choi, Sangkyu; Chung, Suk-Ho ( 0000-0001-8782-312X )
Abstract:
The characteristics of laminar lifted flames of pre-vaporized n-heptane in coflow jets were investigated under both non-autoignited and autoignited conditions by varying the initial temperature. The fuel tested was n-heptane considering the importance as a primary reference fuel for gasoline and its low temperature ignition behavior at relatively low pressure. The results showed that the lifted flame edge in the non-autoignited regime had a tribrachial structure with lean and rich premixed flame wings together with a trailing diffusion flame. The liftoff heights correlated reasonably well with the fuel jet velocity scaled by the stoichiometric laminar burning velocity regardless of the initial temperature and the nitrogen dilution. The liftoff velocity multiplied by the buoyancy-induced velocity and the blowout velocity scaled by the mole fraction of the fuel correlated well with the stoichiometric laminar burning velocity. When the initial temperature was above 900. K, flames were autoignited without any external ignition source. Autoignited lifted flames with both tribrachial edges and mild combustion characteristics were observed. The correlation of the liftoff height with the calculated adiabatic ignition delay time was weak, unlike in cases with gaseous fuels of C1-C4 hydrocarbons in which the liftoff height of the autoignited flames correlated well with the square of the adiabatic ignition delay time. When the mole fraction of the fuel was small, mild combustion behaviors were exhibited with edge flames without distinct tribrachial structures. The liftoff height was correlated with the fuel jet velocity scaled by the initial fuel mass fraction, while the dependence on the ignition delay time was weak when compared with the gaseous fuels. © 2013 The Combustion Institute.
KAUST Department:
Clean Combustion Research Center; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Combustion and Laser Diagnostics Laboratory
Publisher:
Elsevier BV
Journal:
Combustion and Flame
Issue Date:
Sep-2013
DOI:
10.1016/j.combustflame.2013.03.028
Type:
Article
ISSN:
00102180
Sponsors:
This work was supported by Saudi Aramco.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorChoi, Sangkyuen
dc.contributor.authorChung, Suk-Hoen
dc.date.accessioned2015-08-03T11:15:48Zen
dc.date.available2015-08-03T11:15:48Zen
dc.date.issued2013-09en
dc.identifier.issn00102180en
dc.identifier.doi10.1016/j.combustflame.2013.03.028en
dc.identifier.urihttp://hdl.handle.net/10754/562927en
dc.description.abstractThe characteristics of laminar lifted flames of pre-vaporized n-heptane in coflow jets were investigated under both non-autoignited and autoignited conditions by varying the initial temperature. The fuel tested was n-heptane considering the importance as a primary reference fuel for gasoline and its low temperature ignition behavior at relatively low pressure. The results showed that the lifted flame edge in the non-autoignited regime had a tribrachial structure with lean and rich premixed flame wings together with a trailing diffusion flame. The liftoff heights correlated reasonably well with the fuel jet velocity scaled by the stoichiometric laminar burning velocity regardless of the initial temperature and the nitrogen dilution. The liftoff velocity multiplied by the buoyancy-induced velocity and the blowout velocity scaled by the mole fraction of the fuel correlated well with the stoichiometric laminar burning velocity. When the initial temperature was above 900. K, flames were autoignited without any external ignition source. Autoignited lifted flames with both tribrachial edges and mild combustion characteristics were observed. The correlation of the liftoff height with the calculated adiabatic ignition delay time was weak, unlike in cases with gaseous fuels of C1-C4 hydrocarbons in which the liftoff height of the autoignited flames correlated well with the square of the adiabatic ignition delay time. When the mole fraction of the fuel was small, mild combustion behaviors were exhibited with edge flames without distinct tribrachial structures. The liftoff height was correlated with the fuel jet velocity scaled by the initial fuel mass fraction, while the dependence on the ignition delay time was weak when compared with the gaseous fuels. © 2013 The Combustion Institute.en
dc.description.sponsorshipThis work was supported by Saudi Aramco.en
dc.publisherElsevier BVen
dc.subjectAutoignitionen
dc.subjectLifted flameen
dc.subjectLiftoff heighten
dc.subjectMild combustionen
dc.subjectN-Heptaneen
dc.titleAutoignited and non-autoignited lifted flames of pre-vaporized n-heptane in coflow jets at elevated temperaturesen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentCombustion and Laser Diagnostics Laboratoryen
dc.identifier.journalCombustion and Flameen
dc.contributor.institutionEnvironmental and Energy Systems Research Division, Korea Institute of Machinery and Materials, Daejeon, South Koreaen
kaust.authorChoi, Sangkyuen
kaust.authorChung, Suk-Hoen
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