Session: Student Poster Competition

Submission Number: 187177

Design and Validation of an Emissions Analyzer for an Ammonia-Fueled Aircraft Engine 

Ammonia has recently gained interest in the field of combustion research because of its potential as a hydrogen carrier. Hydrogen fuel is not currently scalable because of challenges with its low energy density at ambient conditions, high explosivity, and strong tendency to leak. Ammonia presents solutions to many of these challenges. Liquid ammonia has a significantly higher volumetric energy density than liquid hydrogen, a lower explosivity, and a larger molecular structure to mitigate leaks. Also, the infrastructure to safely transport ammonia currently exists due to its widespread use in fertilizer manufacturing and refrigeration.

Although ammonia presents several advantages over hydrogen, it also comes with new challenges. These include narrow flammability limits, lower flame speeds, higher ignition temperatures and the tendency to produce toxic emissions products (NH₃ and NO_x). Cracking ammonia into N₂ and H₂ before combustion improves its combustion properties, but challenges with emissions still exist. All these challenges must be addressed before ammonia can be implemented as an aviation fuel.

The VASU Labs group at UCF is working to conduct the first demonstration of the use of ammonia in an aircraft turbine engine using a General Electric J85. Ammonia will be injected in its gaseous form, requiring the design of new fuel injectors, as the factory injectors are designed for liquid Jet-A. Before running the engine, a testing campaign will be conducted to study the performance of different fuel injector geometries, fuel blends, and equivalence ratios.

This poster presents the design and validation of a customized emissions analyzer capable of measuring NH₃ slip in engine exhaust plumes. The system employs laser absorption spectroscopy (LAS) with a 10.4-micron quantum cascade laser, a linearly actuating emissions probe, heated stainless steel sampling lines to prevent condensation and adsorption, and a modular optical cell for adaptable measurements. A sampling-based approach was chosen instead of an in situ measurement technique to mitigate beam steering effects and allow for exhaust conditioning before measurements.

 This system will first be used during the fuel injector testing campaign to identify which configurations minimize ammonia emissions, and these results will be presented at the poster session. Its modularity allows for future adaptation to J85 exhaust measurements, NO_x detection with gas drying, and advanced noise-reduction techniques such as wavelength modulation spectroscopy (WMS).

This work demonstrates a practical approach to real-time emissions monitoring in both aircraft and land-based turbines powered by ammonia. This methodology may also serve as a low-cost, reliable solution to species measurements in applied combustion experiments using other alternative fuels.

Presenting Author: Aaron Guenther University of Cental Florida

Presenting Author Biography: Aaron is a graduate student at the University of Central Florida pursuing a PhD in Mechanical Engineering. He graduated from UCF in 2025 with his undergraduate degree in Aerospace Engineering and received the DoD NDSEG fellowship during that year to pursue his graduate studies. He currently works under Dr. Subith Vasu conducting applied combustion research on the application of ammonia as an aircraft turbine fuel. He was born in Tampa and has resided in the state of Florida for his whole life.

Authors:

Aaron Guenther University of Cental Florida
David Zamora University of Central Florida
Christopher Loving University of Central Florida
Thuy-Linh Le University of Central Florida
Subith Vasu University of Central Florida
Justin Urso University of Central Florida
Jayanta Kapat University of Central Florida
Ramees Khaleel Rahman University of Central Florida