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Reducing emissions and fuel consumption in supersonic aviation with ammonia hybrid engines

2025· article· en· W4412792350 on OpenAlex
Muhammad Mueed Khan, Olabode Ajenifujah

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueInternational Journal of Hydrogen Energy · 2025
Typearticle
Languageen
FieldEnvironmental Science
TopicAdvanced Aircraft Design and Technologies
Canadian institutionsUniversity of Waterloo
Fundersnot available
KeywordsFuel efficiencyAviationSupersonic speedEnvironmental scienceAmmoniaAutomotive engineeringConsumption (sociology)Greenhouse gasNitrogen oxidesThrust specific fuel consumptionWaste managementChemistryAerospace engineeringEngineering

Abstract

fetched live from OpenAlex

Ammonia, emerging as a zero-carbon aviation fuel, presents potential for high-energy hydrogen storage and rapid conversion medium to electricity. Recent electrification efforts in the aviation industry further reinforces its importance as electricity direct storage has challenges especially in terms of their low energy density and maximum attainable airspeed with motor-propellers. This study explores a supersonic hybrid electric engine for medium-haul airlines, combining ammonia-powered turbofan with a proton exchange membrane fuel cell. Mathematical modeling helps generate parametric dataset across different flight phases which is then used for training a physics-informed artificial neural network to identify optimum design points in terms of safety, efficiency and emissions. The hybrid engine outperforms legacy aircraft like the Concorde and subsonic turbofans fueled with either ammonia or fossil kerosene; achieving around 18% reduction in specific fuel consumption and about 31% lower NOx pollutants. Moreover, maintaining high fuel cell power draw-down towards the fan for propulsion also helps achieve greater overall efficiencies than non-hybrids and further ensures that the engine core has enough residual power to operate safely, even after loss of single engine core during flight. Additionally, contrail analysis reveals that the ammonia-fueled PEMFC hybrid forms up to 70% fewer ice crystals than hydrocarbon-based systems, potentially lowering climate forcing of resulting contrails. However, due to higher water vapor emission indices and lower exhaust temperatures, contrails from the hybrid engine can form at ambient temperatures up to 20–30 K warmer than those required by conventional engine configurations.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.377
Threshold uncertainty score0.221

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.008
GPT teacher head0.236
Teacher spread0.228 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it