TY - JOUR
T1 - Pulsed laser heating of diesel engine and turbojet combustor soot
T2 - Changes in nanostructure and implications
AU - Vander Wal, Randy L.
AU - Singh, Madhu
AU - Bachalo, William
AU - Payne, Greg
AU - Manin, Julien
AU - Howard, Robert
N1 - Funding Information:
The authors are grateful to the U.S. EPA who funded the VARIAnT 3 field campaign and invited our participation. Dr. Robert Howard and Arnold Engineering Development Complex, (AEDC) TN, U.S. Air Force are gratefully acknowledged for supporting Artium Technologies, Inc.’s participation in the VARIAnT 3 campaign, the laboratory experiments, and analyses. The authors acknowledge Naneos for lending a Naneos Partector TEM sampler with which some of the TEM grids were sampled. HRTEM characterization was conducted using the microscopy facilities of the Materials Research Institute at The Pennsylvania State University. HRTEM guidance from Drs. Jennifer Gray and Ke Wang is gratefully acknowledged. The following VARIAnT 3 team members are acknowledged for their contributions: John Kinsey1, Bob Giannelli2, Jeffrey Stevens2, Cullen Leggett2, Robert Howard3, Brandon Hoffman3, Mary Forde3, Alla Zelenyuk-Imre4, Kaitlyn Suski4, Richard Frazee5, Tim Onasch6, Andrew Freedman6, David Kittelson7 and Jake Swanson7 1Formerly with the US Environmental Protection Agency, Office of Research and Development, Center for Environmental Measurement and Modeling, Research Triangle Park, NC 27711, USA, currently retired. 2US Environmental Protection Agency, National Vehicle and Fuel Emissions Laboratory (NVFEL), Ann Arbor, MI 48105, USA. 3US Air Force, Arnold Engineering Development Complex (AEDC), Arnold AFB, TN 37389, USA. 4US Department of Energy, Pacific Northwest National Laboratory (PNNL), Richland, WA 99352, USA. 5Singularity Scientific Consulting Services, LLC, Whitmore Lake, MI 48189, USA. 6Aerodyne Research Inc., Billerica, MA 01821, USA. 7Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
Publisher Copyright:
©, This work was authored as part of the Contributor's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 USC. 105, no copyright protection is available for such works under US Law.
PY - 2023
Y1 - 2023
N2 - Carbonaceous particulate produced by a diesel engine and turbojet engine combustor are analyzed by transmission electron microscopy (TEM) for differences in nanostructure before and after pulsed laser annealing. Soot is examined between low/high diesel engine torque and low/high turbojet engine thrust. Small differences in nascent nanostructure are magnified by the action of high-temperature annealing induced by pulsed laser heating. Lamellae length distributions show occurrence of graphitization while tortuosity analyses reveal lamellae straightening. Differences in internal particle structure (hollow shells versus internal graphitic ribbons) are interpreted as due to higher internal sp3 and O-atom content under the higher power conditions with hypothesized greater turbulence and resulting partial premixing. TEM in concert with fringe analyses reveal that a similar degree of annealing occurs in the primary particles in soot from both diesel engine and turbojet engine combustors—despite the aggregate and primary size differences between these sources. Implications of these results for source identification of the combustion particulate and for laser-induced incandescence (LII) measurements of concentration are discussed with inter-instrument comparison of soot mass from both diesel and turbojet soot sources.
AB - Carbonaceous particulate produced by a diesel engine and turbojet engine combustor are analyzed by transmission electron microscopy (TEM) for differences in nanostructure before and after pulsed laser annealing. Soot is examined between low/high diesel engine torque and low/high turbojet engine thrust. Small differences in nascent nanostructure are magnified by the action of high-temperature annealing induced by pulsed laser heating. Lamellae length distributions show occurrence of graphitization while tortuosity analyses reveal lamellae straightening. Differences in internal particle structure (hollow shells versus internal graphitic ribbons) are interpreted as due to higher internal sp3 and O-atom content under the higher power conditions with hypothesized greater turbulence and resulting partial premixing. TEM in concert with fringe analyses reveal that a similar degree of annealing occurs in the primary particles in soot from both diesel engine and turbojet engine combustors—despite the aggregate and primary size differences between these sources. Implications of these results for source identification of the combustion particulate and for laser-induced incandescence (LII) measurements of concentration are discussed with inter-instrument comparison of soot mass from both diesel and turbojet soot sources.
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U2 - 10.1080/02786826.2023.2244548
DO - 10.1080/02786826.2023.2244548
M3 - Article
AN - SCOPUS:85168607491
SN - 0278-6826
VL - 57
SP - 1044
EP - 1056
JO - Aerosol Science and Technology
JF - Aerosol Science and Technology
IS - 10
ER -