Browse Topic: Jet fuel

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Thermal Management System in Commercial Aircraft: A Case Study on Passenger Egress System2026-26-07606/1/2026
It is known fact that Thermal management systems are essential to the safety, operational efficiency, and structural integrity of present-day commercial aircraft. Very critical insulation and thermal protection materials are utilized across various aircraft zones to mitigate extreme temperature challenges, ranging from cryogenic conditions at high altitude to pyrotechnic conditions at low altitude/ sea level. Some of the examples where specific materials at their functional role are, In engine pylons and nacelles, high temperature alloys such as Titanium and Inconel, along with ceramic Matrix composites (CMCs) serve as firewalls and heat shields, which are designed to contain fires and protect primary structures. In bleed air ducting, fiberglass or silica insulations blankets are employed to prevent thermal degradation of surrounding aluminum and composite components, when air at temperatures above 200 degree C flows. This paper focuses on the critical insulation and thermal protection materials on passenger Egress system utilized to mitigate pyrotechnic events. The focused case study on passenger egress system highlights a unique application of thermal protection. As these system, as mandated by FAA TSO-C69c, must ensure the system remains deployable and structurally stable for at least 90 seconds under intense heat exposure, preserving a workable egress path for passengers. The passenger egress system surface functions as a heat resistance barrier, resisting thermal energy from potential post-crash jet fuel fire. The heat barrier materials are polymer coated with woven nylon, impregnated with a metallic/ Ceramic layer. This study will emphasize how tailored material coating solutions are fundamental to addressing the diverse and extreme thermal demands in aerospace design, directly contributing to passenger’s safety and aircraft survivability.
Govindaraju, Parthasarathy, Nanjundegowda, Harshavardhana
Conceptual Design of Hydrogen Fuel-Cell-Based Utility Aircraft2026-26-07836/1/2026
The aviation industry contributes to around 2% of global carbon dioxide emissions. As various sectors of the economy look to reduce their global carbon footprint, the aviation industry is positively acknowledging alternatives to jet fuel. Hydrogen proves to be one such alternative having a high energy density and producing zero carbon emissions on combustion. Hydrogen when used in a jet engine produces water vapour and NOx emissions. In order to reduce the effect of GHGs, the current study aims to develop aircraft concepts suitable with hydrogen propulsion through fuel cells for a short-haul commercial mission profile. Aircrafts such as Metro-23 and Dornier 228-212 were referenced for the requirements of a utility turboprop aircraft. The weight estimation was done to obtain the take-off weight of 10,863 kg following the optimization of thrust to weight ratio and wing loading to calculate the initial dimensions. OpenVSP was used to model the initial structure of the aircraft. For the propulsion system, the PEM fuel cell was sized for the aircraft to achieve a range of 2,065 km and endurance of 6 hours in two configurations. Also, various configurations of fuel tanks and their positions were analyzed. The design was able to achieve a reduction of up to 18% in the propulsion system weight through fuel stack configuration. Iterations were performed to achieve static stability and CG was estimated to be 31% of root chord. The final configuration layout with cabin seats, propellers, fuel tank and fuel cells were analysed for static stability. The flight performance of the aircraft is comparable to the reference aircrafts. The proposed design leads towards the path of sustainable aviation.
Bhattacharya, Anisha, Seetha Ramu, Sree Valli, C N, Lakshmi Manasa, Rohit, Benjamin
Advanced Silicone Materials for Harsh Aerospace Environments26AERP06_016/1/2026
Aerospace and defense systems demand materials capable of maintaining performance under extreme environmental and operational stressors, including wide thermal cycling ranges, exposure to hydrocarbon fuels, vacuum conditions, and repeated mechanical strain. Silicone-based materials have become essential in these environments because they can retain elasticity, stability, and functionality where many traditional materials fail. Silicones are widely used as coatings, adhesives, sealants, and elastomers in aircraft and spacecraft applications. Their chemical structure enables resistance to both high and low temperatures, while also providing durability against solvents and fuels such as jet fuel. In contrast, many conventional elastomers degrade under prolonged thermal exposure or become brittle at cryogenic temperatures.
Sustainable Aviation Fuels – A Review of the Challenges Associated to the Aviation’s Net Zero Commitment2025-36-021812/18/2025
The aviation sector currently accounts for 2-3% of global Greenhouse Gas (GHG) emissions, while the projected increased air travel demand (average 3.4% per year), might surge the aviation fuel use. This increase in jet fuel demand, associated with the current decarbonization pathway of other sectors might increase the aviation’s absolute emissions, as well as its relative global GHG share. This scenario has driven the aviation stakeholders into a decarbonization strategy, focused on an immediate and gradual GHG reduction effort associated with a net-zero commitment by 2050. Meanwhile, the aviation sector is known as one that set most difficulties to use alternative fuels and/or powertrains, such as battery electric or sustainable hydrogen fueled propulsion systems, already used on some road and rail applications, but still restricted to the aviation, due to the inherent weight and volume tight requirements. In this context, the sustainable aviation fuels (SAF) are set as the most promising short and medium term aviation decarbonization tool, due to their drop-in feature, which ultimately allows its use on the current aircraft fleet, as well as the fuel storage and distribution systems, provided the certified blends. The prominent SAF role brings increasing demand volumes in the foreseeable future. However, the SAF scaling process from the current 0.1% share of the global jet fuel market faces an array of challenges (technical, regulatory – including the sustainability associated with the feedstocks and the production pathways and economic), requiring collective efforts to boost the technology deployment, address demand reliability and set an efficient regulatory frameworks. Different regulatory approaches have been proposed, with the so called mandates, adopted, for instance, in the European Union and to be adopted in Brazil (from 2027), to encourage investments for SAF production, while the United States (U.S.), the larger jet fuel market in the world, has adopted the use of incentives, to foster the SAF production capacity. This work presents, in a review format, a chronological timeline of the challenges associated with the implementation and scale use of SAF. It highlights the technical, regulatory and economic topics associated with the aviation’s net zero commitment, as well as sets the required roles of the associated stakeholders to make SAF a feasible alternative.
Barbosa, Fábio Coelho
Glossary of Terms - Aircraft Ground Refueling and DefuelingAIR4783B (Current)11/18/2025
This SAE Aerospace Information Report presents a glossary of terms commonly used in the ground delivery of fuel to an aircraft and pertinent terms relating to the aircraft being refueled.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Optimal Sets of Molecules to Predict Aviation Fuel Properties2025-01-039510/7/2025
The complexity and variability of modern aviation fuels necessitate the development of robust and efficient tools to assess their properties accurately, particularly within the certification framework established by the American Society for Testing and Materials (ASTM). Therefore, previous research has developed predictive models to reduce the experimental burden by predicting aviation fuel properties from broad chemical classes. While two-dimensional Gas Chromatography (GC×GC) provides detailed compositional information, it only identifies the weight of hydrocarbon families (aromatics, cycloalkanes, n-alkanes, iso-alkanes), not individual molecules. Aviation fuels are complex, and their composition can contain more than 60 key classes, the majority of which are isomeric. As a result, an exceptionally high number of possible molecule combinations makes random selection prone to high errors in property prediction. To this end, we used a Monte Carlo approach to search for the optimal combination of 64 hydrocarbon molecules from this vast combinatorial space. By exploring up to 500 million combinations, we aim to determine the molecule set that best predicts mass density, kinematic viscosity, and distillation temperature using linear mixing rules. These rules calculate the properties of molecule mixtures using the weight of each molecule in the mixture and the pure molecules’ properties. We used experimental data for various aviation fuels, including conventional jet fuels, sustainable aviation fuels, and rocket propulsion fuels. Results showed that the isomeric effect has a substantial role in predicting mass density, kinematic viscosity, and the distillation temperature. Results showed that the linear mixing rules could outperform machine learning that overlooks the isomeric effect for the three properties. This research benefits the surrogate fuel analysis, which requires defining a surrogate mixture of hydrocarbon molecules, and will provide insights into the best isomers or molecules to choose to predict aviation fuel properties with the least error. This work will help deliver aviation fuel producers with a relatively accurate pre-screening tool for property prediction, minimizing the need for iterative experimental processes.
Radaideh, Mohammed I., Kim, Doohyun, Radaideh, Majdi, Violi, Angela
Aerospace Fuel System Specifications and StandardsAIR1408B (Current)7/16/2025
This report lists documents that aid and govern the design of aircraft and missile fuel systems. The report lists the military and industry specifications and standards and the most notable design handbooks that are commonly used in fuel system design. Note that only the principle fuel specifications for the U.S. and Europe (Military Specifications, ASTM, and Def Stan) have been included within this report. The specifications and standards section has been divided into two parts: a master list arranged numerically of all industry and military specifications and standards, and a component list that provides a functional breakdown and a cross-reference of these documents. It is intended that this report be a supplement to specifications ARP8615, MIL-F-17874, and JSSG 2009. Revisions and amendments which are correct for the specifications and standards are not listed. The fuel system design handbooks are listed for fuels and for system and component design.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Aircraft Fuel System and Component Icing TestARP1401C (Current)6/27/2025
This SAE Aerospace Recommended Practice (ARP) covers a brief discussion of the icing problem in aircraft fuel systems and the different means that have been used to test for icing. Fuel preparation and icing test procedures for aircraft fuel systems and components are proposed herein as a recommended practice to be used for fixed wing and rotary-wing aircraft within their operational environment. This ARP mostly addresses aircraft fuel system level testing and provides a means to address the requirements of FAR 14 CFR § 23.951(c), § 25.951(c), § 27.951(c), and § 29.951(c). In the context of this ARP, the engine and the auxiliary power unit (APU) are not considered to be components of the aircraft fuel system. However, some of the methods described in this document can be applied to the engine, APU, and other aircraft (system or component level) icing tests. This revision does not completely address new developments in ice accretion and release resulting from internal flow in tubing (see 2.3.6). This will be addressed in a different document when more experimental data is available.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Evaluation of Jet Fuels on Thermal Efficiency, NO X Emissions, Particulate Matter, and Particle Size Distribution in a Heavy-Duty Compression Ignition Engine2025-01-02446/16/2025
Alternative fuels such as Fischer-Tropsch Synthesized Paraffinic Kerosene (FT-SPK) and Catalytic Hydrothermal Conversion Jet (CHCJ) are among the important sustainable aviation fuels (SAFs) for future transportation. However, these alternative fuels often vary in their characteristics, depending on their feedstock and fuel production processes. Therefore, a detailed analysis of these alternative fuels' combustion, emissions, and efficiency must be performed under controlled experiments to understand the impact of fuel properties and operating conditions. This study used a single-cylinder research engine (SCE) with a compression ratio of 17:1. Extensive operating conditions were performed to determine the effect of each fuel on the engine performance, which can be fundamentally understood by fuel properties (e.g., cetane number, heat of combustion, and density) in comparison with Jet-A fuel. The experimental setup includes high-speed data acquisition for combustion analysis and gaseous and solid emissions benches for nitrogen oxides (NOX). Results suggested that an engine control management (ECM) strategy can potentially optimize the performance of these alternative jet fuels by compensating for differences in their fuel properties. This study aims to provide insights for future work on exploring different SAF fuels that are more environmentally friendly while meeting the required performance.
Cung, Khanh, Miganakallu Narasimhamurthy, Niranjan, Khalek, Imad, Hansen, Greg
Impact of Copper Contamination on the Thermal Stability of Jet FuelsAIR6443A (Current)5/27/2025
This SAE Aerospace Information Report (AIR) discusses the sources of copper in aviation jet fuels, the impact of copper on thermal stability of jet fuels and the resultant impact on aircraft turbine engine performance, and potential methods for measurement of copper contamination and reduction of the catalytic activity of copper contamination in jet fuels. This document is an information report and does not provide recommendations or stipulate limits for copper concentrations in jet fuels.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
A Conjugate Heat Transfer Numerical Framework Applied to Energy-Assisted Ignition of Jet Fuel in a Rapid Compression Machine2025-01-83524/1/2025
Airborne compression ignition engines operating with aviation fuels are a promising option for reducing fuel consumption and increasing the range of hybrid-electric aircraft. However, the consistent ignition of Jet fuels at high-altitude conditions can be challenging. A potential solution to this problem is to ignite the fuel sprays by means of a glow-plug-based ignition assistant (IA) device. The interaction between the IA and the spray, and the subsequent combustion event result in thermal cycles that can significantly affect the IA’s durability. Therefore, designing an efficient and durable IA requires detailed understanding of the influence that the IA temperature and insertion depth have on the complex physics of fuel-air mixture ignition and flame propagation. The objective of this study is to design a conjugate heat transfer (CHT) modeling framework that can numerically replicate F-24 Jet fuel spray ignition using a glow-plug-based IA device in a rapid compression machine (RCM). A new phenomenological energy source model has been introduced to simulate the heat generation inside the heating element of the IA. The thermodynamic state prior to the spray injection is accurately modeled by simulating the RCM compression process. The ignition and combustion events were simulated using two different approaches, i.e., via a multi-component surrogate fuel and single-species surrogate fuel reaction mechanisms. Comparisons against experimental data of time evolution of the IA’s temperature showed that the CHT framework accurately predicts the IA’s transient heating process prior to spray injection. This approach avoids the need for ad-hoc, case-by-case calibration of the IA preheating duration in numerical simulations. Also, comparisons against available experimental data for reacting sprays showed that the multi-component surrogate fuel approach not only correctly predicts the volumetric and spray ignition modes but also captures the IA temperature for which the transition between the two combustion modes occurs.
Oruganti, Surya Kaundinya, Lien, Hao-Pin, Torelli, Roberto, Motily, Austen, Lee, Tonghun, Kim, Kenneth, Mayhew, Eric, Kweon, Chol-Bum
SAE TOMORROW TODAY: A Breakthrough in Sustainable Aviation Fuel135022/17/2025
We often hear about sustainable fuel options when it comes to vehicles, but what about aerospace? With aviation fuel demand expected to rise to 160 billion gallons per year by 2050, new and innovative Sustainable Aviation Fuel (SAF) pathways are certainly needed. In response, CleanJoule has developed a proprietary manufacturing process that produces SAF with 10% higher energy density than average Jet A fuel. This process utilizes abundant biomass residue to create a cost-effective, drop-in replacement for conventional jet fuel. To learn more, we sat down with Mukund Karanjikar CEO, to discuss CleanJoule's mission is to create accessible, affordable and abundant SAF and reduce the aerospace industry's reliance on fossil fuels. We'd love to hear from you. Share your comments, questions and ideas for future topics and guests to podcast@sae.org. Don't forget to take a moment to follow SAE Tomorrow Today--a podcast where we discuss emerging technology and trends in mobility with the leaders, innovators and strategists making it all happen--and give us a review on your preferred podcasting platform. Follow SAE on LinkedIn, Instagram, Facebook, Twitter, and YouTube. Follow host Grayson Brulte on LinkedIn, Twitter, and Instagram.
Hineman, Marcie
Experimental Evaluation of Binary Iso-Dodecane/n-Dodecane Blends for Emulating Sooting Characteristics of Sustainable Aviation Fuels01-18-01-00032/6/2025
Sustainable aviation fuels (SAFs) derived from renewable sources are promising solutions for achieving carbon neutrality and further controlling aircraft engine emissions, operating costs, and energy security. These SAFs, primarily consist of branched and normal paraffins and exhibit significantly reduced sooting tendencies compared to conventional petroleum-based jet fuels, due to their lack of aromatics content. Our previous study investigated soot formation in non-premixed combustion for three ASTM-approved alternative jet fuels, namely Fischer–Tropsch synthetic paraffinic kerosene (FT-SPK), hydroprocessed esters and fatty acids from camelina (HEFA-Camelina), and alcohol-to-jet (ATJ), and demonstrated that the varying paraffinic composition within SAFs results in diverse sooting propensities, in the order of ATJ > FT-SPK > HEFA-Camelina. To evaluate the impact of iso-paraffins on sooting tendency and validate the suitability of utilizing binary blends of iso-dodecane (iC12) and normal dodecane (nC12) as surrogates for emulating sooting characteristics of SAFs, an experimental study was conducted to measure the soot volume fraction profiles of iC12/nC12 blends with varying blending ratios in the counterflow non-premixed flame configuration using laser-induced incandescence technique. It is shown that ATJ and HEFA-Camelina can be well-represented by pure iC12 and the blend of 25% iC12 and 75% nC12 (in liquid volume), respectively. At high (low) reactant concentrations, the blend of 75% iC12/25% nC12 (90% iC12/10% nC12) exhibits similar sooting characteristics of FT-SPK. The present experimental results indicate that binary blends of iC12 and nC12 have the potential to serve as effective surrogates for SAFs, as they are predominantly composed of these two types of paraffinic components. Furthermore, it is found that when the iC12 blending ratio exceeds 90%, the maximum soot volume fraction exhibits a stronger nonlinear increase. This experimentally observed nonlinearity in maximum soot volume fraction with increasing alkane branching in the binary fuel blend signifies the importance of fuel molecular structure effects on soot formation pathways in counterflow non-premixed flames.
Xue, Xin, Sung, Chih-Jen, Wang, Xiaofeng
Aerospace & Defense Technology: February 202525AERP022/6/2025
The Art of Reverse Engineering Yesteryear for Aerospace and Defense Data Storage Drives Manufacturing Spotlight: Machining Complex Parts and Materials for Space Flight and Exploration Notre Dame's New Boundary Breaking Mach 10 Quiet Wind Tunnel Shape-Shifting Antenna Poised to Transform Communications British Army Completes First Test of Drone Killing Radio Frequency Weapon A Swarm of Sensors, Rovers and Astronauts Explore the 'Moon' Researchers at the German Aerospace Center have developed a new approach to networked communications that could theoretically occur on the Moon or in environments on Earth where conventional communications are unavailable. Army Researchers Examine Nanotechnology for Climate Solutions Army scientists are joining forces with experts from across the nation to tackle the climate crisis using the power of nanotechnology Airman Brings Fuel Sampling Innovation to Eglin, Possibly Air Force The U.S. Air Force is testing a new prototype single point nozzle adapter that drastically reduces the time required for jet fuel quality sampling. Atomic Fountain for Research in Quantum Sensing Nears Completion of First Phase Naval Postgraduate School (NPS) physicists are on track to bring the institution's new atomic fountain online - the largest of its kind in the world - for applications to quantum sensing experiments in precise navigation and timekeeping. Revolutionizing the Waves: A Breakthrough in Surf Observation Technology for Sailors and Marines A team of Army and Navy scientists and engineers have developed a real-time sensing technology for deciding whether conditions are suitable for landing troops on enemy shores.
Blended-Wing Body Airplane Tradeoffs: H2 vs. Jet FuelSM_H2_2025-54132/2/2025
Blended-Wing Body Airplane Tradeoffs: H2 vs. Jet Fuel
Kerr, Ryan
Aircraft Safety: Jet Fuel vs. HydrogenSM_H2_2025-54082/2/2025
Aircraft Safety: Jet Fuel vs. Hydrogen
Damazo, Jason, Simitz, Lauren
Sustainable Aviation Fuel – An Effective Tool for Complying with the Aviation’s Global Environmental Commitment2024-36-006612/20/2024
The (commercial) aviation sector (passenger and freight), which is strongly engaged with the world efforts to mitigate the carbon emissions and their inherent climate change effects, has accounted in 2018 for 2.4 % of global carbon dioxide (CO2) emissions (pre-pandemic levels). Despite the reductions in air travel demand during the 2020 pandemic, with a reduction of up to 80% in passenger travel during the peak pandemic period, the air travel demand has already recovered to around 80% of the pre-pandemic level, with aviation emissions in 2022 reaching around 800 Mt CO2, accounting for 2% of the global energy related CO2 emissions. Moreover, the demand for air travel is expected to double by 2040, growing at an annual average rate of 3.4%, which means that. despite the efficiency improvement trend (average 2%/year), will almost double the aviation’s greenhouse (GHG) emissions, with a significant increase in its relative GHG share, compared to the other transport modes. Meanwhile the aviation sector is one of the hardest to decarbonize, with few and costly pathways available. Zero emissions technologies, such hydrogen fuel and electric batteries are currently far from commercially ready for aviation use in the short to medium term, due to the technical challenges, such as aircraft onboard liquid hydrogen storage difficulties, as well as battery weight and volume, and are unlikely ever to be able to power large or long-haul flights. In this scenario, the so called sustainable aviation fuel (SAF), a drop-in fuel concept, already available in modest amounts on a commercial scale, are seen as a promising short to medium term alternative to tackle aviation emissions, by using existing aircraft designs and infrastructure. As a drop-in fuel, the SAF enables the replacement for the fossil jet fuel by using the existing fuel delivery and storage infrastructure and existing aircraft engines, with lifespan that still ranges from 20 to 30 years. From a chemical perspective, the SAF is the liquid aviation fuel derived from non fossil carbon resources, such as biomass or organic derived waste feedstocks, as well as synthetic fuels produced from carbon capture and renewable energy sources. They might be currently used in blends with fossil jet fuel, with current blending limits ranging from 5% to 50%, depending on the feedstock and production pathway. It is estimated from the International Air Transport Association (IATA) that to reach the net zero emission commitment, by 2050, around 65% of emission reductions should be reached by replacing conventional jet fuel with SAF. Despite its important role in the aviation decarbonization, the SAF share currently makes up only 0.1% of aviation fuel demand, which requires a huge increase in the production capacity, which might face challenges, such as feedstock availability, fuel sustainability and cost competitiveness. This work presents a review of the SAF technology, with a focus on the production pathways and their environmental footprint, their use on current aircraft engines and the associated required blends, as well as the challenges associated with SAF production increase and cost reductions, still required to make it a realistic aviation decarbonization tool.
Barbosa, Fábio Coelho
Effect of Fuel Chemical Structure on Soot Formation in Sustainable Aviation Fuels2024-01-431011/5/2024
Sustainable Aviation Fuels (SAFs) offer great promises towards decarbonizing the aviation sector. Due to the high safety standards and global scale of the aviation industry, SAFs pose challenges to aircraft engines and combustion processes, which must be thoroughly understood. Soot emissions from aircrafts play a crucial role, acting as ice nuclei and contributing to the formation of contrail cirrus clouds, which, in turn, may account for a substantial portion of the net radiative climate forcing. This study focuses on utilizing detailed kinetic simulations and soot modeling to investigate soot particle generation in aero-engines operating on SAFs. Differences in soot yield were investigated for different fuel components, including n-alkanes, iso-alkanes, cycloalkanes, and aromatics. A 0-D simulation framework was developed and utilized in conjunction with advanced soot models to predict and assess soot processes under conditions relevant to aero-engine combustion. The simulations, conducted under combustion and inert conditions, revealed that aromatic fuels significantly enhance soot yield, exhibiting accelerated growth toward larger aromatics under both combustion and pyrolysis conditions. The results also highlight the necessity for higher gas temperatures for PAHs to grow, in agreement with pyrolysis experiments indicating soot onset temperatures between 1400 and 1500K. Furthermore, the study assessed the influence of precursors on soot formation, challenging the appropriateness of using C2H2 or mono-aromatics as precursors with the tested soot models. The simulation results indicate that such precursors lead to large errors, advocating for the use of larger PAHs as precursor in these soot models, as suggested by the models’ validation space. Finally, this work also explores the impact of fuel structure on soot formation, contributing to ongoing efforts to replace aromatics with cycloalkanes in jet fuels through examining reference fuel blends representative of petroleum-based jet fuel and cycloalkane-based SAFs. The “SAF” blends result in a reduced soot yield compared to the jet fuel surrogate, underscoring SAFs’ capability to diminish emissions in the aviation industry.
Yi, Junghwa, Manin, Julien, Wan, Kevin, Lopez Pintor, Dario, Nguyen, Tuan, Dempsey, Adam
Experimental and Numerical Investigations of a Dual-Fuel Hydrogen–Kerosene Engine for Sustainable General Aviation2024-01-60016/17/2024
Reducing CO2 emissions is an increasingly important issue. In aviation, approaches such as e-propulsion only represent a solution for special applications due to the low energy density of batteries. Because of the low-cost and robust design of combustion engines, this concept is still the most suitable for general aviation. For defossilization, besides e-fuels and bio-fuels, which represent the so-called sustainable aviation fuels (SAF), hydrogen can serve as a promising energy carrier for CO2 reduction. For this purpose, the combustion process of a dual-fuel hydrogen–kerosene (Jet A-1) engine was developed and investigated for use in small aircrafts. This study explores the influence of hydrogen addition on combustion parameters, emissions, and efficiency. An advantage of this special design as dual-fuel engine (hydrogen and kerosene) is the possibility of redundancy operation in the event of a H2 fuel system failure as well as full operational capability of the aircraft in the event of hydrogen supply difficulties at various airports. Besides test bench investigations, 3D CFD simulations were performed to optimize hydrogen injector position, ensure backfire-free operation, and improve mixture formation. In addition to a low load and high load point, a high-altitude point was investigated based on real flight data. The maximum achievable hydrogen energy shares, limited by abnormal combustion, and the respective CO2 reductions are shown. Furthermore, the influence of the hydrogen mass distribution in the inlet ports was investigated to achieve an advantage in the homogenization of the hydrogen–air mixture. Finally, the efficiency losses in hydrogen dual-fuel mode compared to base kerosene operation are shown in a detailed analysis.
Reitmayr, Christian, Wiesmann, Frederik, Gotthard, Thomas, Hofmann, Peter
Compression Ignition Engine Smoke Emissions at Reduced Ambient Pressures and Temperatures2024-01-23804/9/2024
Smoke emission from compression ignition (CI) engines is directly tied to fuel atomization, vaporization, mixing and combustion processes. Engine boundary conditions such as ambient pressures and temperatures, particularly at higher altitudes, have significant impacts on both available ignition energy and on the mixing-controlled combustion process. However, the effects of boundary conditions are difficult to explore without thorough pressure and temperature control of the engine intake air and exhaust gas at higher altitude conditions. The objective of this research is to investigate the relationship between engine smoke emission and engine power in a CI engine fueled with jet fuel at various ambient conditions including higher altitudes. A multi-cylinder compression-ignition engine was operated on a jet fuel at various ambient pressure and temperature conditions, as low as 60 kPa and -12°C, respectively. Single and multi-injection strategies were applied depending on engine power. Detailed analysis was made on in-cylinder pressure, heat release, and the ratio of premixed combustion to mixing-controlled combustion as indicated by the heat release rate. Smoke opacity and filtered smoke number (FSN) measurements were made using an AVL Opacimeter and an AVL Smoke Meter, respectively, at sea level conditions as well as at reduced ambient temperatures and pressures. Depending on the engine power, a shift between premixed and mixing-controlled combustion occurred which significantly impacted the engine-out smoke. Further, the smoke emission was dependent on the injection strategies. Smoke emissions for the jet-fueled engine were examined with respect to heat release behavior and equivalence ratio. The capabilities and challenges of measuring smoke at higher altitude conditions are discussed.
Mattson, Jonathan, Gibson, Joseph, Kweon, Chol-Bum, Kim, Kenneth, Schroen, Erik, Hepp, Kyle, Meininger, Rik, Clerkin, Peter, Kruger, Kurt, Musser, Marshall, Pope, Aaron, Kang, Sang-Guk
Impact of a Split-Injection Strategy on Energy-Assisted Compression-Ignition Combustion with Low Cetane Number Sustainable Aviation Fuels2024-01-26984/9/2024
The influence of a split-injection strategy on energy-assisted compression-ignition (EACI) combustion of low-cetane number sustainable aviation fuels was investigated in a single-cylinder direct-injection compression-ignition engine using a ceramic ignition assistant (IA). Two low-cetane number fuels were studied: a low-cetane number alcohol-to-jet (ATJ) sustainable aviation fuel (SAF) with a derived cetane number (DCN) of 17.4 and a binary blend of ATJ with F24 (Jet-A fuel with military additives, DCN 45.8) with a blend DCN of 25.9 (25 vol.% F24, 75 vol.% ATJ). A pilot injection mass sweep (3.5-7.0 mg) with constant total injection mass and an injection dwell sweep (1.5-3.0 ms) with fixed main injection timing was performed. Increasing pilot injection mass was found to reduce cycle-to-cycle combustion phasing variability by promoting a shorter and more repeatable combustion event for the main injection with a shorter ignition delay. For both fuels, dwells between 2.0 and 2.5 ms resulted in the lowest variability. For these dwells, the pilot injection cumulative heat release at the main injection timing is maximized, resulting in more rapid ignition of the main injection. Emissions results suggest that mixing-controlled combustion of the main injection is achievable with higher pilot masses at injection dwells between 2.0 and 2.5 ms as indicated by an increase in filter smoke number at these conditions.
Stafford, Jacob, Amezcua, Eri, Miganakallu Narasimhamurthy, Niranjan, Kim, Kenneth, Kweon, Chol-Bum, Rothamer, David
Zero Carbon Emission Aviation Fuel Technology Review - The Hydrogen Pathway2023-36-00291/8/2024
The commercial aviation currently accounts for roughly 2.5 % of the global CO2 emissions and around 3.5% of world warming emissions, taking into account non CO2 effects on the climate. Its has grown faster in recent decades than the other transport modes (road, rail or shipping), with an average rate of 2.3%/year from 1990 to 2019, prior to the pandemic. Moreover, its share of Greenhouse (GHG) emissions is supposed to grow, with the increasing demand scenario of air trips worldwide. This scenario might threaten the decarbonization targets assumed by the aviation industry, in line with the world efforts to minimize the climate effects caused by the carbon emissions. In this context, hydrogen is set as a promising alternative to the traditional jet fuel, due to its zero carbon emissions. Furthermore, its high energy content makes it suitable for the aviation industry, especially in the short to medium haul flights niche, that currently accounts for around 43.8% of global aviation CO2 emissions. Hydrogen fueled aircrafts might have fewer range limitations, compared with battery electric counterparts, currently restricted to smaller commuter flights, given the low energy density of the batteries. For long range flights, liquid fuels alternatives, such as sustainable aviation (SAF), still have a leading position in the short to medium term environmental agenda. Hydrogen can be burned directly in (modified) gas turbine engines, in fuel cells, to generate electricity to power electric motors, or in hybrid-electric propulsion systems. Nevertheless, despite the environmental benefits, there are great challenges to make hydrogen a viable alternative to the fossil liquid jet fuel. One of the main hurdles is the fuel storage, associated with the much higher volume and storage system complexity required for (liquid) hydrogen, to provide the same amount of energy of liquid jet fuel. These fuel features require aircraft and engine design modifications, as well as a new fuel distribution infrastructure. Another major challenge is the full understanding of the non CO2 related climate impacts of hydrogen combustion, such as H2O emissions at cruise altitudes, which interacts with soot and particles in the atmosphere, to form contrails. Finally, the H2 cost, might be addressed to enable a fair competition with fossil jet fuel. Currently, there is a great research effort, from both the government and academic sectors, as well as from the aircraft manufacturers, which includes the test of demonstration H2 aircraft prototypes. This effort also might include policies to foster environmental friendly fuel alternatives, to make them cost competitive. This work presents a review of the aviation hydrogen technology, with a focus on both the propulsion and onboard storage systems, as well as on the potential environmental benefits and the associated costs of the aviation hydrogen fuel pathway. The review research has been supported on a wide search on the technical literature, by using up to date (mainly published in the last two years) articles, whitepapers and technical reports, available at specialized directories and scientific journals. The search has used key words, such as aviation sustainability, hydrogen for aviation propulsion, aviation environmental footprint (and Greenhouse emissions) reduction, as well as liquid and gaseous hydrogen storage.
Barbosa, Fábio Coelho
Emissions of Aerospace Fuels F-24 and Jet-A in a Jet Engine and Correlation with Combustion Characteristics from a Constant Volume Combustion Chamber2023-01-166610/31/2023
An investigation into emissions differences and their correlations with differing combustion characteristics between F24 and Jet-A was conducted. Raw emissions data was taken from a single stage jet engine by a FTIR gas analyzer. Measurements of H2O, CO2, CO, NOx, and total hydrocarbon emissions (THC) were taken at 60K, 65K, and 70K RPM. At 70K RPM Jet-A and F-24 the emissions were similar at approx.: 4% H2O, 3% CO2, 970 PPM CO, 28 PPM NOx. Jet-A THC emissions were approx.: 1200 PPM THC, F24 THC emissions were lower by over 60%. The significantly lower amount of THC emissions for F24 suggests more complete combustion compared to Jet-A.
Soloiu, Valentin, Rowell, Aidan, Weaver, Amanda, Mcafee, John, Willis, James, O'Brien, Brandon
Comparative Analysis of the Lubrication, Friction, and Wear of Injection System Materials, with Synthetic Paraffinic Kerosene, Jet-A, and ULSD2023-01-163310/31/2023
Alternative fuels are sought after because they produce lower emissions and sometimes, they have feedstock and production advantages over fossil fuels, but their wear effects on engine components are largely unknown. In this study, the lubricity properties of a Fischer-Tropsch Gas-to-Liquid alternative fuel (Synthetic Paraffinic Kerosene-S8) and of Jet-A fuel were investigated and compared to those of Ultra Low Sulphur Diesel (ULSD). A pin-on-disk tribometer was employed to test wear and friction for a material pair of an AISI 316 steel ball on an AISI 1018 steel disk when lubricated by the fuels in this research work. Advanced digital microscopy was used to compare the wear patterns of the disks. Viscosity and density analysis of the tested fluids were also carried out. Tribometry for the fuel showed that S8 fell between Jet-A and ULSD when friction force was calculated and showed higher wear over time and after each test when compared to that of Jet-A and ULSD. An initially higher running-in friction force of 0.35N to 0.38N was observed for all three tested fluids, and then quasi-steady-state lower values of friction force of .310N for S8, 0.320 N for Jet-A and 0.295N for ULSD (the lowest observed).Wear values obtained by mass loss of the tested AISI 108 steel disks show that Jet-A and the reference fuel ULSD may yield lower wear (which is associated to better lubricity) than that of S8, and microscopy images are consistent with the wear results.
Soloiu, Valentin, Davis, Zachary, Molina, Gustavo J., Myrthil, Christopher, Willis, James, Weaver, Amanda
Development of a Laboratory Unit to Study Internal Injector Deposits Formation2023-24-00788/28/2023
The formation of deposits in the fuel systems of heavy-duty engines, using drop-in fuels, has been reported in recent years. Drop-in fuels are of interest because they allow higher levels of alternative fuels to be blended with conventional fuels that are compatible with today’s engines. The precipitation of insolubles in the drop-in fuel can lead to clogging of fuel filters and internal injector deposits, resulting in increased fuel consumption and engine drivability problems. The possible mechanisms for the formation of the deposits in the fuel system are not yet fully understood. Several explanations such as operating conditions, fuel quality and contamination have been reported. To investigate injector deposit formation, several screening laboratory test methods have been developed to avoid the use of more costly and complex engine testing. To further evaluate and understand the formation of internal injector deposits in heavy-duty engines, a thermal laboratory test method has been developed. The test method is called Thermal Deposits Test (TDT) and it is inspired by Jet Fuel Thermal Oxidation Test (JFTOT) method. This test unit can be used to study in applications where a fluid is in contact with a hot surface. The method uses common laboratory hardware and readily available off-the-shelf parts, making it inexpensive to build and very flexible to operate. Deposits are collected on a metal foil, which makes it easier to analyze. This paper describes the construction of the apparatus and its performance. Experimental tests with diesel fuel, doped with soap-type soft particles, which contain typical particles that can form deposits, are performed, and compared with JFTOT results. Analytical techniques, such as Scanning Electron Microscopy with Energy Dispersive X-Ray, Fourier-transform Infrared Spectroscopy, and Pyrolysis coupled with Gas Chromatography-Mass Spectroscopy and Ellipsometry were used. Conclusions about the performance of the doped fuel are drawn from the test. Future plans are to study the mechanisms behind the formation of internal diesel injector deposits.
Pach, Mayte, Hittig, Henrik, Scholle, Tobias, Kusar, Henrik, Engvall, Klas
Experimental and Numerical Investigation of Combustion and Noise, Vibrations, and Harshness Emissions in a Drone Jet Engine Fueled with Synthetic Paraffinic Kerosene01-17-01-00068/14/2023
Emissions and effects of climate change have prompted study into fuels that reduce global dependence on traditional fuels. This study seeks to investigate engine performance, thermochemical properties, emissions, and perform NVH analysis of Jet-A and S8 using a single-stage turbojet engine at three engine speeds. Experimental Jet-A results were used to validate a CFX simulation of the engine. Engine performance was quantified using thermocouples, pressure sensors, tachometers, flow meters, and load cells fitted to the engine. Emissions results were collected using an MKS Multigas Emissions Analyzer that examined CO, CO₂, H₂O, NOx, and THC. NVH analysis was conducted using a multifield, free-field microphone, and triaxial accelerometer. This study found that Jet-A operates at higher temperatures and pressures than S8, and S8 requires higher fuel flow rates than Jet-A, leading to poorer efficiency and thrust. S8 produced stronger vibrations over 5 kHz compared to Jet-A. S8 showed a decrease in all measured emissions. The CFD model was validated, showing an increase in temperature, pressure, and gas velocity as speed increased. The swirl effect of combustion was examined, improving atomization. Emissions contours were validated by experimental results, showing increases in CO₂, H₂O, and NOx, and a decrease in CO as speed increases.
Soloiu, Valentin, Mcafee, John, Ilie, Marcel, Rowell, Aidan, Willis, James, Dillon, Nicholas
On-Board Fuel Sensing for UAS and Ground Vehicle Applications2024-01-41288/10/2023
The variability in fuel, particularly for fuel blends containing sustainable aviation fuels (SAFs), emphasizes the importance of understanding fuel properties for optimizing engine performance. This paper introduces spectroscopic fuel sensors capable of real-time estimation of jet fuel properties, mainly derived cetane number (DCN). While initially developed for unmanned aircraft systems (UAS), the paper explores their potential in ground vehicle applications: enhancing engine performance through sensing for feed-forward control and fuel property monitoring at fuel depots. The fuel sensing technologies are based on spectroscopic techniques coupled with machine learning (ML) approaches. The combination of these techniques demonstrates a promising solution for a wide spectrum of fuel applications.
Patel, Dev B., Sutar, Ashish, Abraham, Abhinav, Ambre, Dhananjay, Brezinsky, Kenneth, Lynch, Patrick T., Okada, Haruna, Stafford, Jacob M., Miganakallu, Niranjan, Sanders, Scott, Rothamer, David, Mayhew, Eric, Kim, Kenneth S.
Extension of Diesel Engine Power via Electrically Assisted Turbocharger2024-01-41368/10/2023
The power demand for unmanned ground systems (UGS) and unmanned aircraft systems (UAS) has been ever-increasing to support important military operations. Mild hybridization technologies have the potential to address the ever-increasing power demand. The objective of this study is to investigate the capability of an electrically assisted turbocharger (EAT) as one mild hybridization method. A motor-generator (M/G) was integrated to a turbocharger to generate electricity using the engine exhaust energy, or to spin the turbocharger using the energy stored in energy storage device. The EAT was implemented to a 2-liter turbocharged direct-injection diesel engine fueled with jet fuel. Then, the operation of the EAT was examined and the results were compared to the baseline. The target manifold pressure was regulated by the M/G, which applies varying amounts of positive or negative torque to increase or decrease the speed of the EAT. The energy recovered from the exhaust stream and converted to electricity by the EAT was equal to approximately 5% of the maximum rated engine power. Furthermore, the EAT was able to extend the engine power by 6% at the same equivalence ratio by providing more air to the combustion chamber and in turn more fuel.
Kang, Sang-Guk, Schroen, Erik S., Mattson, Jonathan M., Kim, Kenneth S., Hepp, Kyle D., Kruger, Kurt M., Clerkin, Peter J., Kweon, Chol-Bum M., Gibson, Joseph A., Meininger, Rik D., Musser, Marshall R.
Combined Impacts of Engine Speed and Fuel Reactivity on Energy-Assisted Compression-Ignition Operation with Sustainable Aviation Fuels2023-01-02634/11/2023
The combined impacts of engine speed and fuel reactivity on energy-assisted compression-ignition (EACI) combustion using a commercial off-the-shelf (COTS) ceramic glow plug for low-load operation werexxz investigated. The COTS glow plug, used as the ignition assistant (IA), was overdriven beyond its conventional operation range. Engine speed was varied from 1200 RPM to 2100 RPM. Three fuel blends consisting of a jet-A fuel with military additives (F24) and a low cetane number alcohol-to-jet (ATJ) sustainable aviation fuel (SAF) were tested with cetane numbers (CN) of 25.9, 35.5, and 48.5. The ranges of engine speed and fuel cetane numbers studied are significantly larger than those in previous studies of EACI or glow-plug assisted combustion, and the simultaneous variation of engine speed and fuel reactivity are unique to this work. For each speed and fuel, a single-injection of fixed mass was used and the start of injection (SOI) was swept for each IA power. A maximum pressure rise rate (MPRR) limit of 20 bar/CAD and a coefficient of variation of gross indicated mean effective pressure (COV of IMEPg) limit of 5% were used as the bounds for the safe SOI operating range. Results demonstrated that the use of an ignition assistant at a high input power (70 W) can significantly increase the range of SOIs that fall within the prescribed safe operating range. For the higher cetane number fuels (35.5 and 48.5), that burn well without the IA, an advancement in start of combustion (SOC) and combustion phasing were observed with operation of the IA at 70 W. For the low CN fuel (25.9), which misfired without the use of the IA, complete combustion could be achieved with the use of the IA at 70 W. At higher engine speeds, the effectiveness of the IA diminishes. To better understand why the IA effectiveness decreased, a thermocouple was used to measure the IA tip surface temperature in-cylinder. Under motored engine conditions with fixed IA power, the IA surface temperature decreased as engine speed increased. The lower IA surface temperature along with the shorter time available as engine speed increased contributed to the decreased effectiveness at higher engine speeds.
Stafford, Jacob, Amezcua, Eri, Miganakallu Narasimhamurthy, Niranjan, Kim, Kenneth, Kweon, Chol-Bum, Rothamer, David
Comparison and Evaluation of Engine Wear, Engine Performance, NOx Reduction and Nanoparticle Emission by using Gasoline, JP-8, Karanja Oil Methyl Ester Biodiesel, and Diesel in a Military 720 kW, Heavy-Duty CIDI Engine Applying EGR with Turbo Charging2023-01-03184/11/2023
Rapid depletion of petroleum crude oil resources, stringent regulations on gaseous emission, and global warming due to exhaust pollution have compelled us to use the alternative of diesel fuel. Biodiesel is a green alternative fuel that can be produced from edible as well as non-edible vegetable oils, waste cooking frying oils, and animal fats. Biodiesel is an oxygenated, bio-gradable, renewable, non-sulfur, and non-toxic fuel. JP-8 is an aviation turbine fuel and is readily available. Gasoline fuel is also available in surplus. Under the multi-fuel strategy program, optimization of fuel availability is required for both, military combat as well as highway commercial heavy-duty vehicles. It was essential to assess the performance, NOx reduction, nanoparticle emission, and engine wear by using Gasoline, JP-8, and esterified Karanja oil biodiesel fuels on a military heavy-duty diesel engine. EGR is a useful technique to reduce NOx emissions. A Military heavy-duty,12-cylinders,720 kW, compression ignition diesel injection (CIDI) engine was operated using all three test fuels applying 10% EGR. All tests were conducted at different engine speeds with load conditions between 20% and 100%. A slight deterioration (2-5%) in engine performance was observed for Gasoline, JP-8, and KOME biodiesel fuels as compared to diesel fuel. NOx emission was reduced by 15-26% along with lowered nanoparticle emission when the engine was operated with Gasoline, JP-8, and KOME biodiesel fuels. Engine wear was found maximum (1-2.6%) with Gasoline and JP-8 fuel.
Pandey, Anand Kumar, Nandgaonkar, Milankumar, Varghese, Anil, sonawane, C, Kohil, Ritesh, Warke, Arundhati
Hydrogen Fuel System for Aircraft2023-01-09763/7/2023
Hydrogen propulsion is crucial for achieving zero carbon emissions in commercial aviation. The aircraft’s power can be generated through hydrogen combustion in a gas turbine engine and electricity through the fuel cell. Though promising, it poses several challenges for implementation, such as the large volume and structural modification required to carry cryogenic liquid hydrogen (LH2). Also, the current jet fuel system used in commercial aviation needs significant changes to incorporate hydrogen aircraft. The primary objective of this study was to analyze the Hypothesis related to Liquid Hydrogen Aircraft, which will help define the hydrogen fuel system. The theories were: A pressurization system is essential to maintain the LH2 tank pressure within the safe limit, Gaseous hydrogen transformed from Liquid Hydrogen is suitable for tank pressurization, Possible to maintain Cryogenic tank conditions during night non-operation time. A simplified Aircraft Hydrogen system was modeled and analyzed for 120 minutes of flight operation and 360 minutes of ground non-operation. The analysis shows that tank insulations are crucial in deciding tank pressurization and cryogenic equilibrium.
Sarkar, Subrata, Grandi, Giada, Patel, Sahil
Synthetic Jet Fuels from Non-Petroleum Feed StocksAIR6148 (Current)2/20/2023
This SAE Aerospace Information Report (AIR) provides general information on the developing subject of synthetic jet fuels derived from non-petroleum feed stocks. It addresses synthetic jet fuel properties and other topics associated with their use and is intended as a guide to assist aviation fuel system designers in considering important information on fuel properties when designing aircraft fuel systems and components. The AIR is limited to “drop-in” fuels that meet the requirements of the respective fuel specifications and are compatible with typical aircraft and ground refueling systems. While some key properties are included in this AIR for discussion, the reader should utilize documents such as MIL-HDBK-510 or the ASTM International research reports for a more-detailed review of fuel properties. AIR7484 also gives more details on fuel properties, specifically as they relate to airframe fuel system design.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Adhesive, Film Form Metallic Structural Sandwich ConstructionAMSA25463 (Current)10/4/2022
This specification covers the requirements for adhesives in film form for bonding metal facings to metal cores and to metal components of sandwich panels which are intended for use in primary and secondary structural airframe parts that may be exposed to temperatures up to 500°F (260°C).
AMS P17 Polymer Matrix Composites Committee
Bubble-Point Test MethodARP901B (Current)9/30/2022
This test method describes a procedure for measuring the largest pore or hole in a filter or similar fluid-permeable porous structure. A standard referee test method for precise determination or resolution of disputes is specified. A simpler inspection test procedure for quality assurance “go-no-go” measurement is also given. Bubble-point testing physics, analysis of bubble-point test data, and correlation with other methods of pore size determination are separately discussed in the appendix.
A-6C1 Fluids and Contamination Control Committee
Lignin-Based Jet Fuel Packs More PowerTBMG-465709/1/2022
An experimental plant-based jet fuel could increase engine performance and efficiency, while dispensing with aromatics, the pollution-causing compounds found in conventional fuels, according to new research.
Primer, Adhesive, Corrosion-Inhibiting High Durability Epoxy, -55 to +175 °C (-67 to +347 °F)AMS3107/3A (Current)8/10/2022
This specification covers a corrosion-inhibiting, modified epoxy resin primer in the form of a ready-to-use, sprayable liquid.
AMS P17 Polymer Matrix Composites Committee
Primer, Adhesive, Corrosion-Inhibiting High Durability Epoxy, -55 to +120 °C (-67 to +248 °F)AMS3107/2A (Current)8/10/2022
This specification covers a corrosion-inhibiting, modified epoxy resin primer in the form of a ready-to-use, sprayable liquid.
AMS P17 Polymer Matrix Composites Committee
Primer, Adhesive, Corrosion-Inhibiting High Durability Epoxy, -55 to +215 °C (-67 to +419 °F)AMS3107/4A (Current)8/10/2022
This specification covers a corrosion-inhibiting, modified epoxy resin primer in the form of a ready-to-use, sprayable liquid.
AMS P17 Polymer Matrix Composites Committee
Primer, Adhesive, Corrosion-Inhibiting High Durability Epoxy, -55 to +95 °C (-67 to +203 °F)AMS3107/1A (Current)8/10/2022
This specification covers a corrosion-inhibiting, modified epoxy resin primer in the form of a ready-to-use, sprayable liquid.
AMS P17 Polymer Matrix Composites Committee
Aerospace, Slipper Seals, Selection for Fluid Power ApplicationsAIR1244B (Current)8/5/2022
This SAE Aerospace Information Report (AIR) provides basic information on the use of slipper seal sealing devices when used as piston (OD) and rod (ID) seals in aerospace fluid power components such as actuators, valves, and swivel joints, including: The definition of a slipper seal and the description of the basic types in use. Guidelines for selecting the type of slipper seal for a given design requirement are provided in terms of friction, leakage, service life, installation characteristics, and interchangeability.
A-6C2 Seals Committee
Investigation of Water Droplet Size Distribution in Conventional and Sustainable Aviation Turbine Fuels04-15-03-00165/17/2022
Water droplet size variation has been established in the literature as an important variable that influences the behavior and characteristics of water in fuel emulsion. However, with the growing demand for sustainable aviation fuels (SAF), no data is available that shows how these fuels will affect the size of dispersed water droplets and their frequency distribution. To address this lack of knowledge, this study explores and presents experimental results on the characterization of dispersed water droplets in alternative fuels and Jet A-1 fuel under dynamic conditions. The alternative fuels comprised of two fully synthetic fuels, two fuels synthesized from bio-derived materials, and one bio-derived fuel. The data and statistics presented reveal that water droplet frequency and size distribution are sensitive to changes in fuel composition. Observations showed an evident transition of the droplet percentile over time in the cumulative frequency distribution; this could be attributed to droplet coalescence to form larger droplets. Mean droplet diameters between 3 and 6 μm were observed for all the fuels tested. With further analysis based on recommendations proposed in this work, the data may assist in providing insight to filter manufacturers. Value of Data/Highlights The dataset provides the aviation industry with insight into the behavior of dispersed water droplets in various commercially available sustainable aviation fuels. The data and statistics presented reveal that water droplet size/count distribution can be influenced by fuel composition. With further analysis based on recommendations proposed in this work, the standardization of test specifications can be improved.
Ugbeh Johnson, Judith, Carpenter, Mark, Okeke, Nonso Evaristus, Nnabuife, Somtochukwu Godfrey, Mai, Nathalie
Aircraft Turbine Engine Fuel System Component Endurance Test Procedure (Room Temperature Contaminated Fuel)MAP749C (Current)5/2/2022
This SAE Aerospace Recommended Practice describes a method for conducting room temperature, contaminated fuel, endurance testing when the applicable specification requires nonrecirculation of the contaminants. The objective of the test is to determine the resistance of engine fuel system components to wear or damage caused by contaminated fuel operation. It is not intended as a test for verification of the component's filter performance and service life. ARP1827 is recommended for filter performance evaluation.
AE-5B Aircraft and Engine Fuel and Lubricant Sys Components
Ignition Sensitivity Analysis for Energy-Assisted Compression-Ignition Operation on Jet Fuels with Varying Cetane Number2022-01-04433/29/2022
Local deposition of thermal energy can be used to assist the combustion process of low cetane number (CN) fuels in compression-ignition engines, here termed energy-assisted compression ignition (EACI). In the current work, a commercial ceramic glow plug, operated beyond its conventional operation range, was used as the ignition assistant (IA) and sensitivity of fuel jet ignition to operation parameters was studied for two fuels using EACI in an optical engine. A design-of-experiments (DoE) study was devised to determine which engine parameters influenced the energy-assisted pilot injection ignition process the most. The DoE was constructed with four parameters: injection pressure, injected mass, injection timing, and ignition assistant temperature. The fuels used were F24 (Jet-A with military additives) with a cetane number of 48 and a cetane number 35 fuel mixture consisting of 60% F24 and 40% of an alcohol-to-jet fuel (ATJ), blended on a volumetric basis. Simultaneous OH chemiluminescence and schlieren imaging were employed along with in-cylinder pressure measurements to assess ignition delay, jet development, and the combustion process. A Gaussian Kriging emulator was utilized to perform the sensitivity analysis. The results indicate that ignition of the fuel jet directed toward the ignition assistant is mainly driven by the ignition assistant temperature, with around 90% of the sensitivity for both fuels ascribed to ignition assistant temperature. However, for ignition assistant surface temperatures greater than ~1350 K ignition delay is approximately constant with increasing temperature. Ignition delay from the time the fuel reaches the ignition assistant to start of combustion, here termed hot surface ignition delay, was analyzed to gain a better understanding of the EACI ignition process. The hot surface ignition delay for ignition assistant temperatures >1350 K ranged from approximately 200 to 500 μs, independent of fuel cetane number. This indicates that ignition for ignition assistant surface temperatures >1350 K is likely the result of high-temperature ignition chemistry.
Amezcua, Eri R., Kim, Kenneth, Rothamer, David, Kweon, Chol-Bum
Power to Liquid (PtL) Synthetic Aviation Fuel - A Sustainable Pathway for Jet Fuel Production2021-36-00342/4/2022
Aviation industry currently accounts for almost 3% of worldwide greenhouse gas (GHG) emissions. Despite the continuous efforts to reduce this environmental footprint, with the use of technological efficiency driven solutions and operational changes to reduce climatic effects, such as engine improvements, fleet renewals and navigation operational improvements, the industry, which is permanently challenged by the continuously stringent standards, is aware of the need of additional measures to tackle, and even reduce, the GHG emissions, by decoupling the world's industry average growth (almost 4.1% annually) to the aviation's carbon emissions. Given its inherent operational features, the aviation sector requires fuels with high specific energy and energy density. This technical requirement makes the well known clean and efficient electrical propulsion technology to be limited to niche aviation segments (short range and low capacity airplanes) in the short and medium terms. In this scenario, the so called Sustainable Aviation Fuels(SAF) - non fossil hydrocarbons, manufactured with renewable & sustainable feedstocks - appear as the big bet for the carbon footprint reduction for the medium and long range aviation. The biofuel SAF pathway, i.e. that which relies on biological feedstocks (crops and waste), already certified and produced to be used in blends with fossil jet fuel, into a drop-in fuel concept, has some environmental limitations associated with GHG net emissions, cost, and natural resources (land use and water) requirements. These limitations might set sustainable challenges to a massive future biofuel based SAF approach. In this context, the so called Power to Liquids (PtL) fuels, which comprises the production of synthetic liquid hydrocarbon fuels, using renewable electricity (for hydrogen generation with water electrolysis) and non fossil carbon dioxide (CO2) as the main feedstocks, is seen as a promising SAF pathway. Compared to biofuels, PtL SAF reaches higher area-related yields, with the intensive use of renewable electricity, such as photovoltaic and wind energy. The PtL's SAF water requirement is also significantly lower, compared to the biofuel production. Hence, the PtL SAF technology is seen as an important SAF pathway to enable a non fossil and fully sustainable fuel supply for aviation in the long run, avoiding the risks and adverse effects potentially associated with biomass based pathways. This work presents, based on an assessment of the researched technical literature, an overview of the PtL SAF technology, with a focus on the production methods and the required inputs, followed by an assessment of operational effects and costs for the aviation sector. The analysis shows that the PtL SAF appears as a promising sustainable SAF pathway, with a lower GHG footprint (into a Lyfecycle basis) and reduced water requirement, as well as a higher yield, compared to the plant-based SAF pathways (biofuels). Moreover, PtL SAF does not raise the demand for arable land, avoiding the so called food & fuel conflict. From a technical perspective, the PtL SAF might produce fuels suitable for even a net fossil fuel substitution (no blends). Nevertheless, the PtL SAF costs, which relies strongly on the renewable electricity price, are still a challenge to enable the competition with fossil jet fuel. This might initially require regulatory actions as well as further technological improvements, mainly associated with renewable electricity - fuel conversion and CO2 supply alternatives.
Barbosa, Fábio Coelho
Adhesive Film, Epoxy-Base, High Durability For 215 °C (420 °F) ServiceAMS3695/4 (Current)1/20/2022
This specification covers an adhesive compounded from modified epoxy resins in ready-to-use film supplied in rolls or sheets, either supported by mat or by woven monofilaments or unsupported.
AMS P17 Polymer Matrix Composites Committee
Adhesive Film, Epoxy-Base for High Durability Structural Adhesive BondingAMS3695 (Current)1/20/2022
This specification and its supplementary detail specifications cover film adhesives compounded from modified epoxy resins in the form of ready-to-use sheet, supplied in rolls, either supported by mat or by woven monofilaments or unsupported.
AMS P17 Polymer Matrix Composites Committee
Minimization of Electrostatic Hazards in Aircraft Fuel SystemsAIR1662B (Current)12/21/2021
This SAE Aerospace Information Report (AIR) provides background information, technical data, and related technical references for minimization of electrostatic hazards in aircraft fuel systems.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Reticulated Polyurethane Foam Explosion Suppression Material for Fuel Systems and Dry BaysAIR4170C (Current)12/20/2021
This document describes the initial development, evolution, and use of reticulated polyurethane foam as an explosion suppression material in fuel tanks and dry bays. It provides historical data, design practice guidelines, references, laboratory test data, and service data gained from past experience. The products discussed in this document may be referred to as "Safety Foam," "Reticulated Polyurethane Foam," "Baffle and Inerting Material," or "Electrostatic Suppression Material." These generic terms for the products discussed in this document are not meant to imply any safety warranty. Each individual design application should be thoroughly proof tested prior to production installation.
AE-5D Fuel Tank Flammability Reduction Systems Committee
Shield Termination, Solder Style, Insulated, Heat-Shrinkable, Environment Resistant General Specification forAS83519D (Current)12/13/2021
This specification covers environment resistant, heat-shrinkable solder type shield terminations. They may be used on data-bus, RF, and shielded cables in applications. Operating temperature of each product are as indicated on detail specifications.
AE-8C2 Terminating Devices and Tooling Committee
Products of Tomorrow: December 2021TBMG-4043712/1/2021
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
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