Evaluation of Non-volatile Particulate Matter Emission Characteristics of an Aircraft Auxiliary Power Unit with Varying Alternative Jet Fuel Blend Ratios

Abstract

The aviation industry is increasingly focused on the development of sustainable alternative fuels to augment and diversify fuel supplies while simultaneously reducing its environmental impact. The impact of airport operations on local air quality and aviation related greenhouse * Corresponding author, e-mail address: plobo@mst.edu 2 gas emissions on a life cycle basis have been shown to be reduced with the use of alternative fuels. However, the evaluation of incremental variations in fuel composition of a single alternative fuel on the production of non-volatile particulate matter (nvPM) emissions has not been explored. This is critical to understanding the emissions profile for aircraft engines burning alternative fuels and their impact on air quality and climate change. A systematic evaluation of nvPM emissions from a GTCP85 aircraft auxiliary power unit (APU) burning a 16 different blends of Used Cooking Oil (UCO) derived Hydroprocessed Esters and Fatty Acids (HEFA) type alternative fuel with a conventional Jet A-1 baseline fuel was performed.The nvPM number-and mass-based emission indices for the 16 fuel blends and neat 100% UCO-HEFA were compared against those for the baseline Jet A-1 at the three APU operating conditions. Fuel composition was found to influence nvPM production. The reductions in nvPM were found to be greater with increasing fuel hydrogen content (higher proportion of UCO-HEFA in the fuel blend). For a 50:50 blend of UCO-HEFA and Jet A-1, which would meet current ASTM specifications, the average reduction in nvPM number-based emissions was ~35%, while that for mass-based emissions was ~60%. The nvPM size distributions were found to narrow and shift to smaller sizes as the UCO-HEFA component of the fuel blend increased. This shift has a greater impact on the reduction in nvPM mass compared to the overall decrease in nvPM number, when comparing the blends to the baseline Jet A-1.

Experimental Investigation of Cycle Properties, Noise, and Air Pollutant Emissions of an APS3200 Auxiliary Power Unit

“…To characterize the combustion reaction a global air number (λ gl ), which is the reciprocal of the equivalence ratio, is defined in Eq. (6).…”

“…They present typical indices for gaseous emissions as well as smoke and particle emission data for idle and full power conditions. In a recent publication by Lobo et al [6], the exhaust gas emissions of 16 different blends of alternative fuels compared with a conventional Jet A-1 are shown. The systematic evaluation of emissions was conducted with a Honeywell GTCP85 APU at three different operating conditions.…”

Demonstration of a Regulatory Method for Aircraft Engine Nonvolatile PM Emissions Measurements with Conventional and Isoparaffinic Kerosene fuels

“…A schematic of the sampling and measurement system deployed in this campaign is presented in Figure 1. The sampling and measurement system was fully compliant with the specification outlined in AIR6241 and has been used previously to measure nvPM emissions from a turbofan engine [4] and an aircraft auxiliary power unit [23]. The IPK fuel derived from coal was manufactured by Sasol using the Fischer-Tropsch process.…”

Chemistry characterization of jet aircraft engine particulate matter by XPS: Results from APEX III

“…Field campaigns with multiple teams have measured PM size and number distributions, with others calculating mass emission indices as function of power and fuel type [13][14][15][16][17][18][19][20]. Specific techniques have included scanning mobility particle sizer (SMPS), aerosol mass spectrometers (AMS), providing electric and aerodynamic mobilities, respectively, tapered element oscillator measurement (TEOM) for total PM mass and absorption for black carbon determination in an aethalometer or multi-angle absorption photometer (MAAP) instrument.…”