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Evaluation of Methods for the Determination of Black Carbon Emissions from an Aircraft Gas Turbine Engine
Kinsey, J. AND E. Corporan. Evaluation of Methods for the Determination of Black Carbon Emissions from an Aircraft Gas Turbine Engine. 33rd Annual AAAR Conference, Orlando, FL, October 20 - 24, 2014.
The purpose of this research was to compare four different black carbon measurement methods using real turbine exhaust as a follow-on to a prior laboratory study utilizing a soot generator. Different fuels and engine operating conditions were used to vary the concentration and organic carbon (OC) content of the particulate matter emissions to determine whether the measurements made by the three continuous instruments were sensitive to volatile organics.
The emissions from aircraft gas turbine engines consist of nanometer size black carbon (BC) particles plus gas-phase sulfur and organic compounds which undergo gas-to-particle conversion downstream of the engine as the plume cools and dilutes. In this study, four BC measurement methods were evaluated while sampling the diluted emissions from a T63 turboshaft engine. Multiple fuel types were used in the study to vary the organic carbon content of the particles and concentrations of soot emitted by the engine. The BC methods evaluated were: laser induced incandescence (Artium LII 300); photoacoustic soot sensing (AVL Micro Soot Sensor or MSS); multi-angle absorption photometry (MAAP); and semi-continuous filter sampling with analysis by NIOSH Method 5040. Other supporting parameters measured included particle size distribution, total particle concentrations, sulfur dioxide, unburned hydrocarbons, and smoke number. The data generated by the three on-line analyzers were compared to each other and the elemental carbon (EC) concentration determined by NIOSH 5040. We found that all BC methods were highly correlated to each other for the combined data set with the MAAP having the best overall agreement to NIOSH 5040. With the possible exception of the MAAP at one experimental condition, the continuous analyzers showed little or no apparent dependence to the organic carbon content of the particles generated by the engine. Variations in the MAAP data are believed to have been caused by a faulty valve which was not discovered until the tests were completed.