Effects of ambient temperature and oxygen concentration on diesel spray combustion using a single-nozzle injector in a constant volume combustion chamber

Handle URI:
http://hdl.handle.net/10754/562957
Title:
Effects of ambient temperature and oxygen concentration on diesel spray combustion using a single-nozzle injector in a constant volume combustion chamber
Authors:
Jing, Wei; Roberts, William L. ( 0000-0003-1999-2831 ) ; Fang, Tiegang
Abstract:
This work investigates the effects of ambient conditions on diesel spray combustion in an optically accessible, constant volume chamber using a single-nozzle fuel injector. The ambient O2 concentration was varied between five discrete values from 10% to 21% and three different ambient temperatures (800 K, 1000 K, and 1200 K). These conditions simulate different exhaust gas recirculation (EGR) levels and ambient temperatures in diesel engines. Both conventional diesel combustion and low temperature combustion (LTC) modes were observed under these conditions. A transient analysis and a quasi-steady state analysis are employed in this article. The transient analysis focuses on the flame development from beginning to the end, illustrating how the flame structure changes during this process; the quasi-steady state analysis focuses on the stable flame structure. The transient analysis was conducted using high-speed imaging of both OH* chemiluminescence and natural luminosity (NL). In addition, three different images were acquired using an ICCD camera, corresponding to OH* chemiluminescence, narrow-band flame emission at 430 nm (Band A) and at 470 nm (Band B), and were used to investigate the quasi-steady state combustion process. From the transient analysis, it was found that the NL signal becomes stronger and confined to narrow regions when the temperature and O2 concentration increase during the development of flame. The OH* intensity is much lower for the 10% ambient O2 and 800 K conditions compared to the higher temperatures and O2 levels. This implies the occurrence of LTC under these conditions. Results from the quasi-steady combustion stage indicate that high-temperature reactions effectively oxidize the soot in the downstream locations where only OH* signal is observed. In addition, an area was calculated for each spectral region, and results show that the area of Band A and Band B emissions in these images is larger than the area of OH* emissions at the lower O2 concentrations while the area of OH* emission is larger than the area of Band A and Band B emissions at higher O2 concentrations, for a given ambient temperature. Moreover, the mixture stoichiometry was analyzed using a reformulated definition of excess air ratio for diluted combustion, and this shows that more mixing is required to achieve complete combustion for low ambient oxygen concentration conditions where longer and wider flames are observed. This observation is also verified by the flame length estimated from the NL images. © 2013 Copyright Taylor and Francis Group, LLC.
KAUST Department:
Clean Combustion Research Center; Mechanical Engineering Program; Physical Sciences and Engineering (PSE) Division
Publisher:
Informa UK Limited
Journal:
Combustion Science and Technology
Issue Date:
2-Sep-2013
DOI:
10.1080/00102202.2013.798315
Type:
Article
ISSN:
00102202
Sponsors:
This material is based on work supported by, or in part by, the Faculty Research and Professional Development (FRPD) Fund from the North Carolina State University, the Natural Science Foundation under Grant No. CBET-0854174, and the U.S. Army Research Laboratory and the U.S. Army Research Office under grant W911NF-10-1-0118. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funding agencies.
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.authorJing, Weien
dc.contributor.authorRoberts, William L.en
dc.contributor.authorFang, Tiegangen
dc.date.accessioned2015-08-03T11:16:58Zen
dc.date.available2015-08-03T11:16:58Zen
dc.date.issued2013-09-02en
dc.identifier.issn00102202en
dc.identifier.doi10.1080/00102202.2013.798315en
dc.identifier.urihttp://hdl.handle.net/10754/562957en
dc.description.abstractThis work investigates the effects of ambient conditions on diesel spray combustion in an optically accessible, constant volume chamber using a single-nozzle fuel injector. The ambient O2 concentration was varied between five discrete values from 10% to 21% and three different ambient temperatures (800 K, 1000 K, and 1200 K). These conditions simulate different exhaust gas recirculation (EGR) levels and ambient temperatures in diesel engines. Both conventional diesel combustion and low temperature combustion (LTC) modes were observed under these conditions. A transient analysis and a quasi-steady state analysis are employed in this article. The transient analysis focuses on the flame development from beginning to the end, illustrating how the flame structure changes during this process; the quasi-steady state analysis focuses on the stable flame structure. The transient analysis was conducted using high-speed imaging of both OH* chemiluminescence and natural luminosity (NL). In addition, three different images were acquired using an ICCD camera, corresponding to OH* chemiluminescence, narrow-band flame emission at 430 nm (Band A) and at 470 nm (Band B), and were used to investigate the quasi-steady state combustion process. From the transient analysis, it was found that the NL signal becomes stronger and confined to narrow regions when the temperature and O2 concentration increase during the development of flame. The OH* intensity is much lower for the 10% ambient O2 and 800 K conditions compared to the higher temperatures and O2 levels. This implies the occurrence of LTC under these conditions. Results from the quasi-steady combustion stage indicate that high-temperature reactions effectively oxidize the soot in the downstream locations where only OH* signal is observed. In addition, an area was calculated for each spectral region, and results show that the area of Band A and Band B emissions in these images is larger than the area of OH* emissions at the lower O2 concentrations while the area of OH* emission is larger than the area of Band A and Band B emissions at higher O2 concentrations, for a given ambient temperature. Moreover, the mixture stoichiometry was analyzed using a reformulated definition of excess air ratio for diluted combustion, and this shows that more mixing is required to achieve complete combustion for low ambient oxygen concentration conditions where longer and wider flames are observed. This observation is also verified by the flame length estimated from the NL images. © 2013 Copyright Taylor and Francis Group, LLC.en
dc.description.sponsorshipThis material is based on work supported by, or in part by, the Faculty Research and Professional Development (FRPD) Fund from the North Carolina State University, the Natural Science Foundation under Grant No. CBET-0854174, and the U.S. Army Research Laboratory and the U.S. Army Research Office under grant W911NF-10-1-0118. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funding agencies.en
dc.publisherInforma UK Limiteden
dc.subjectchemiluminescenceen
dc.subjectDiesel engineen
dc.subjectExcess air ratioen
dc.subjectLow-temperature combustionen
dc.subjectNatural luminosityen
dc.subjectOHen
dc.subjectSpray combustionen
dc.titleEffects of ambient temperature and oxygen concentration on diesel spray combustion using a single-nozzle injector in a constant volume combustion chamberen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalCombustion Science and Technologyen
dc.contributor.institutionDepartment of Mechanical and Aerospace Engineering, North Carolina State University, 911 Oval Drive-Campus Box 7910, Raleigh, NC 27695, United Statesen
kaust.authorRoberts, William L.en
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