AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Morphology of Gas Turbine Particulate Matter
ADAM M BOIES, Jacob Swanson, Paul Williams, Amewu A. Mensah, Mark Johnson, Steven Rogak, Jason S. Olfert, Tyler Johnson, Ramin Dastanpour, Gregory Smallwood, Max L. Eggersdorfer, University of Cambridge
Abstract Number: 489 Working Group: Combustion
Abstract Black carbon (BC) emissions from gas turbines impact human health and radiative forcing, but the magnitude of these effects is dependent upon the morphology of the particulate matter (PM). BC characterization is available from a variety of instruments; however a complete analysis of the aerosol concentration, size and morphology only arises by complimentary analysis using in-situ and ex-situ measurement techniques. This work examines characteristics of BC that was generated by a General Electric CFM56-5B4-2P turbofan engine with staged combustion as a part of the SAMPLE III campaign. Gas turbine exhaust aerosol for a range of thrust settings was sampled, conditioned and delivered to a suite of instruments which included catalytic strippers (CS), scanning mobility particle sizers (SMPS), a laser induced incandescence (LII) instrument, a centrifugal particle mass analyzer (CPMA) and aerosol mass spectrometers (AMS). In addition, particles were collected on transmission electron microscopy (TEM) grids via thermophoretic and electrophoretic sampling of polydisperse and monodisperse (mobility selected) PM. In all cases the semi-volatile fraction of the aerosol was removed via a catalytic stripper, leaving the solid PM for in-line characterization or sampling. Measurements by complimentary instruments allow for characterization of distinct metrics of the PM, including particle number concentration and aggregate mobility diameter (SMPS); particle mass concentration and primary particle diameter (LII); aggregate mass (CPMA); and vacuum aerodynamic diameter (AMS). Other metrics, such as the mass-mobility exponent, primary-particle diameter and the aggregate dynamic shape factor are calculated from analytical and modeled relations. The in-situ characterization results are compared to primary particle size and aggregate morphology metrics determined from TEM studies. Key findings include the relation of primary particle diameter, aggregate shape factor and mass mobility exponent as a function of aggregate size and evidence of ash particles present within the soot aggregates.