Abstract View
nvPM Across Decadal Length Scales: Dependence on Biofuel Content
John Kinsey, Bob Giannelli, Jeffrey Stevens, Robert Howard, Mary Forde, Cullen Leggett, Alla Zelenyuk, Kaitlyn J. Suski, Greg Payne, Julien Manin, Richard W. Frazee, Timothy Onasch, Andrew Freedman, Richard Miake-Lye, David Kittelson, Jacob Swanson, RANDY VANDER WAL, Jiawei Liu, Raju Kumal, Penn State University
Abstract Number: 272
Working Group: Combustion
Abstract
Fuel composition has traditionally been assigned tight specifications given the numerous physico-chemical constraints imposed by engine type and operation. A prime example is Jet A, a fuel produced for commercial aviation and used all over the World. With a view towards renewable feedstock as a way to decrease the CO2 footprint associated with air travel, biofuels are receiving an increasing interest. Presently, biofuels are being tested as blends with conventional Jet A fuel, to avoid potential engine damage resulting from injection system’s deposits, lack of lubrication or degradation of elastomer parts (seals and hoses). Biofuels, even blended, offer additional benefits such as reduced black carbon emissions. There is little data on the soot reduction mechanisms in jet engine combustion for such biofuel blends, in part because of the limited access to full-scale engine testing coupled with comprehensive emissions characterization. In this presentation, we provide an overview of black carbon emissions as evaluated by transmission electron microscopy (TEM) analyses of samples collected at the exhaust of a J-85 turbofan engine fueled with Jet A as well as blends of Jet A and Camelina biofuel. Aggregate morphology, primary particle size and their internal nanostructure are analyzed to provide insights into the combustion characteristics. It is hypothesized that aggregate size (and primary particle size) dependence upon power increases with fuel aromatic content, mediated by turbulent fuel air mixing. These tests were conducted by the U.S. Environmental Protection Agency, in cooperation with Arnold Engineering and Development Complex (AEDC, U.S. Air Force), as part of a series of studies entitled VAriable Response In Aircraft nvPM Testing (VARIAnT) field campaigns.