Session: 03-04 Advancements in Turboprop and Turboshaft Engine Technologies

Paper Number: 152708

Particulate and Gaseous Emissions of an Allison 250-C20B Turboshaft Engine Using FT-SPK 

Global warming is one of the biggest challenges of our time. To minimize aviation’s environmental impact, alternatives to fossil-based kerosene are needed. However, complete decarbonization of aviation by electrification or switching to carbon-free fuels will not be possible in the short and medium term. One potential solution is therefore to use Sustainable Aviation Fuels (SAF).

In this paper, a synthetic paraffinic kerosene (SPK) produced using the Fischer-Tropsch (FT) process was tested on an Allison 250 C20B helicopter turboshaft engine to analyze the fuel’s emissions compared to regular Jet A-1. Specifically, three fuel types were tested: conventional Jet A-1, a 50% FT-SPK blend, and 100% pure FT-SPK. The focus of the tests was set to measure the changes in emitted non-volatile particulate matter (nvPM) when using FT-SPK and to compare the results with other alternative aviation fuels, specifically HEFA-SPK. Representative engine load points were selected for the tests, based on the International Civil Aviation Organization's (ICAO) Landing and Take-off-cycle (LTO-cycle).

The nvPM emissions were measured using a scanning mobility particle sizer (SMPS) and a condensation particle counter (CPC). These were employed to characterize the particle number and size distribution. Additionally, an FTIR/FID combination was used to assess key combustion products, including CO₂, NO_X, CO, and the unburned hydrocarbons (UHC). A resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI ToF-MS) was employed as a real-time system to monitor the relative variation in the amount of various polycyclic aromatic hydrocarbons (PAHs) in the exhaust gas for different fuels and load conditions. This approach allows for a more in-depth analysis of the combustion behavior and the formation processes of nvPM.

The particle measurement systems indicate a decrease in particle number when FT-SPK is used. Also, the particle size decreases as more FT-SPK is burned. Interestingly, compared to HEFA-SPK, there is also a significant reduction in gaseous emissions, such as CO and UHC when using FT-SPK. Detailed results and emission analyses for both the particulate and gas phase, along with the results of the REMPI ToF-MS, will be presented in the study.

Presenting Author: Alexander Rabl Technical University of Munich - Institute of Turbomachinery and Flight Propulsion

Presenting Author Biography: 2014-2018: Bachelor of Science in Mechanical Engineering (Technical University of Munich,
Garching)
2018-2021: Master of Science in Aerospace Engineering (Technical University of Munich,
Garching)
2021-now: PhD student and Research Associate (Technical University of
Munich, Garching)

Authors:

Alexander Rabl Technical University of Munich - Institute of Turbomachinery and Flight Propulsion
Marius Rohkamp University of the Bundeswehr Munich - Institute for Aeronautical Engineering
Mohammad Reza Saraji-Bozorgzad University of the Bundeswehr Munich - Institute for Chemistry and Environmental Engineering
Jan Bendl University of the Bundeswehr Munich - Institute for Chemistry and Environmental Engineering
Barbara Giocastro University of the Bundeswehr Munich - Institute for Chemistry and Environmental Engineering
Rares Cotenescu Technical University of Munich - Institute of Turbomachinery and Flight Propulsion
Victor Burger Sasol - Applied Research and Technology
Thomas Adam University of the Bundeswehr Munich - Institute for Chemistry and Environmental Engineering
Andreas Hupfer University of the Bundeswehr Munich - Institute for Aeronautical Engineering
Volker Gümmer Technical University of Munich - Institute of Turbomachinery and Flight Propulsion