Conventional Jet Research Articles

Mixing and Combustion of Methane-Oxygen Flame in a Coaxial Dual-Shear Jet Nozzle

In this study, a coaxial dual-shear jet nozzle is designed to enhance mixing and establish stable methane–oxygen combustion. The characteristics of mixing and combustion of methane–oxygen flames are experimentally investigated in nonreacting and reacting cases by varying the outer-to-middle velocity ratio ru from 1.1 to 5.7. In the nonreacting cases, acetone–planar-laser-induced fluorescence technology is applied to experimentally study the mixing behavior near the nozzle exit. Since the coaxial dual-shear configuration generates a sandwich structure, a flow structure near the exit, including three potential cores and three mixing layers, is established. Two mixture fraction fields divided by a critical velocity ratio ruc are observed, in which the stoichiometric contours have different appearances. Based on the mixing characteristics, a mixing model and a linear scaling relation were presented to predict the stoichiometric mixing length in both nonreacting and reacting flows. Besides, the coaxial dual-shear jets yield more compact flames in cases of ru<2.9, while the conventional coaxial jets produce longer flames with yellow tips. This shows the improvement of the coaxial dual-shear nozzle in mixing and combustion efficiency due to the formation of two shear layers near the nozzle exit. Furthermore, the OH* distribution indicates that the coaxial dual-shear flames produce a lower thermal load on the nozzle, preventing the combustor from experiencing the hazards of ablation.

CFD-Based Study on the Flow and Kinetic Energy Characteristics of a Supercritical Suspended Abrasive Water Jet in the Deep-Sea Environment

A supercritical suspended abrasive water jet with dual inputs of pressure and heat is proposed to improve the cutting performance of the conventional suspended abrasive water jet in deep-sea environments. The paper studies the flow and kinetic characteristics of the supercritical suspended abrasive water jet. The CFD simulation method is proposed to investigate these characteristics by integrating a programmed database of supercritical water material properties with Ansys Fluent. The simulation and comparison show that abrasive particle density, abrasive particle size, inlet pressure, and water temperature affect the acceleration process of the abrasive particles. At the nozzle outlet, the velocity of the abrasive particles reaches over 95% of the supercritical water velocity. With the proposed supercritical abrasive water jet, the jet velocity is increased by 192.2% to 402.40 m/s compared to the conventional suspended abrasive water jet, reducing the amount of water used by 67.7% at a specified temperature of 773.15 K. Correspondingly, the medium kinetic energy is increased by 177.7% and the medium kinetic energy ratio is 2.78. The particle kinetic energy is increased by 723.2% and the particle kinetic energy ratio is 8.23.

Research on performance of jet refrigeration cycle driven by waste heat of refrigerated vehicle

Nowadays, refrigerated food storage and transport vehicles are very common. However, with regard to the engine of vehicles, a significant amount of heat is discharged into the environment in the form of exhaust gas and jacket water. If the cooling system is used to convert this waste heat into cooling capacity, the thermal efficiency of the engine will be improved to a certain extent. Therefore, this paper uses two waste heat recovery jet refrigeration systems to recover heat from the exhaust gas and jacket water of the refrigerated vehicle. One is a conventional jet refrigeration system that uses only engine exhaust as the heat source, and the other is a system that adds a preheater upstream of the generator based on the conventional system, using engine jacket water to preheat the working fluid. This paper presents the results of comparing the impact of R141b/R123, R141b/R245fa, R142b/R134a, and R142b/R152a working fluids on system performance, and considers the effects of operating temperature and secondary flow pressure drop in the ejector receiving chamber on the system performance. The research results indicate that of the four selected working fluids, the R141b/R245fa (0.4/0.6) blend has the best overall performance. After the addition of a preheater, the system using R142b/R134a (0.6/0.4) hybrid working fluid achieves the maximum cooling capacity of 16.0994 kW and the maximum thermal efficiency of 5.45%, and the exergy loss in the generator is 1 kW lower than without the preheater.

Numerical investigation of the thermal efficiency of a multi-nozzle air curtain doorway under different wind conditions

Loading gate openings cause thermal inefficiency due to the substitution of indoor–outdoor air in cold seasons, and as a consequence, escalating energy consumption of warehouse buildings or unloading docks. Research findings have demonstrated that air infiltration/exfiltration through open doors results in the loss of a quarter of annual heating loads in buildings. Air curtains have shown a bright and promising future to compensate for the infiltration rate through the door opening, however, the most prior investigations were allocated to the jet planar air curtains and as yet there is a gap in the literature for other modified air curtain devices, including multi-nozzle air curtains (MNAC) with higher induction and resistance against the strong frontal winds, especially for gates higher than 4.27 m of installation height. Hence, in this work, designed MNAC with various configurations (i.e. large nozzles, small nozzles and holes) and installed on a warehouse loading gate was first characterized using the validated numerical turbulence model, SST (k−ω), to solve governing equations. The validate model is then used to evaluate the MNAC thermal efficiency, using the sensible energy gained by the inside zone, under various outside temperatures (−5, −10, −20, and −30∘C), and two wind conditions (i.e. with and without a front wind as recommended by ASHRAE (2010)). While the air curtains demonstrated limitations in fully controlling the infiltration rate during extremely cold and windy conditions, the results indicate that the MNAC systems have obtained thermal efficiency values higher up to 10% when compared to conventional planar air jets.

Mechanisms of enhanced heat transfer of piston oscillating cooling in a heavy-duty diesel engine

The thermal load and reliability of pistons become major concerns with the increase of power density of internal combustion engines. The oscillating cooling technology is often adopted to enhance the heat transfer of pistons in heavy-duty diesel engines. To understand the heat transfer mechanisms, this study developed an optical oscillating cooling piston based on a real heavy-duty engine. The characteristics of two-phase oscillating flows were optically observed under different conditions. As engine speed increased from 100 to 700 r/min or oil supply pressure decreased from 0.2 to 0.8 bar, the oscillation intensity of the two-phase flow gradually increased and the oscillating flow pattern developed from slug to intermittent mist flow. Furthermore, computational fluid dynamics simulations were performed to analyze the heat transfer mechanisms of oscillating cooling and optimize the structure of the piston. The results showed that the heat transfer coefficient of oscillating cooling can be decomposed into three components, namely conventional flow, oscillation enhanced and jet flushing parts. The conventional flow part accounts for the largest proportion of the total heat transfer coefficient, whose value is positively correlated with oil flow rate. The oscillation enhanced part is optimal when the oil filling rate is between 40 % and 60 %. The jet flushing part can lead to a higher temperature gradient in the outer cooling gallery and thus increased thermal stress. The cooling capacities of inner and outer galleries are mainly influenced by the diameters of the oil outlet and distributor pipes, respectively. The jet flushing part can be controlled by changing the inclination angle of the distributor pipe. Finally, optimization achieved an improvement of 8.3 % in cooling capacity of inner cooling gallery and a reduction of 27.5 % of heat dissipation inhomogeneity in the piston.

PLIF Flame Study on the Qualitative and Quantitative Measurement of OH Species for Conventional and Alternative Jet Fuels; Experimental and Theoretical Investigations

ABSTRACT The hydroxyl molecule is one of the most important intermediate species in the chemistry of combustion processes and plays an important role in the chemical reactions of a hydrocarbon-air flame. However, investigation on a laser-based quantitative measurement of OH in heavy liquid hydrocarbon flames remains very scarce. Thus, in this study, OH radicals were measured qualitatively with the aid of planar laser-induced fluorescence in atmospheric pressure studies of burner stabilized laminar flames of kerosene and alcohol-to-jet (ATJ) fuel. These qualitative profiles were then put on a quantitative basis by analysis of the impact of temperature on the Boltzmann distribution of OH over the ground electronic state rotational energy levels and the use of a simple methane reference flame and its modeling using ANSYS Chemkin-Pro. The quantitative profiles in turn were used to validate the developed chemical kinetic mechanisms of kerosene and ATJ combustion. An experimental apparatus has been developed to investigate the temperature profile and the OH relative amounts of kerosene and ATJ laminar flames in an optimized premixed flat flame burner, under three different air/fuel ratio conditions. Fine wire type thermocouples were applied to provide reliable temperature profiles for the fuel flames. In general, reasonable agreement were observed between the experimental OH results and the simulations for the target fuel flames in the case of kerosene, while a higher peak value of OH was predicted in the ATJ model output compared to the PLIF derived data.

Kinematic viscosity prediction of jet fuels and alternative blending components via comprehensive two-dimensional gas chromatography, partial least squares, and Yeo-Johnson transformation.

This work presents an accurate yet simplified partial least squares model to predict the kinematic viscosity of conventional and alternative jet fuels at -20°C using comprehensive two-dimensional gas chromatography coupled to a flame ionization detector (GC×GC/FID). Three different normalization methods (mean-centering, logarithmic, and Yeo-Johnson) were evaluated to identify their impact in the prediction of middle distillates' physical properties. Results using Yeo-Johnson transformation exhibited improved viscosity prediction capabilities over the validation set with a mean absolute percentage error of 5.3%, a root-mean-squared error of 0.23, and a coefficient of determination (R2 ) of 0.9404 using only 10 latent variables. Unlike previously reported correlations, this model allowed the identification of specific hydrocarbon groups and carbon numbers that drive jet fuel viscosity at low temperatures. The presence of even small amounts of large branched-alkanes (C15 -C17 ), dicyclic-alkanes (C10 ), and cycloaromatics (C11 ) have the potential to strongly increase the kinematic viscosity of jet fuels. Contrastingly, light monocycloalkanes and branched-alkanes (≤ C10 ) were associated with lower viscosity values. Novelly, this model suggests the implementation of Yeo-Johnson transformations to predict the physical properties of middle distillates to further improve the performance metrics of partial least squares models based on GC data.

Diagnostics and characterization of a novel multi gas layer RF atmospheric pressure plasma jet for polymer processing

The quest to employ cold plasma sources at atmospheric pressure in polymer processing has emerged as a potent driving force behind their development. Atmospheric pressure operation of plasma jets provides potential cost reductions as well as easier handling and maintenance. In addition, their unique advantage of remote operation allows the substrate to be placed outside the source boundaries. This latter feature makes it easier to process complex three-dimensional objects and to integrate plasma jets into existing production lines. Although conventional atmospheric pressure plasma jet (APPJ) sources have undergone significant advancements in their design and construction, they have reached their technical and technological thresholds in several domains, thereby also impeding further enhancements in material processing applications. To cope with this issue, this work introduces a promising APPJ (named MPPJ3) working in a three co-axial gas layer geometry, incorporating the capability of aerosol and shield gas introduction leading to a configuration rich in reactive plasma species with controllable size and suitable temperature for polymer processing. A parametric study on the novel MPPJ3 device is carried out and plasma characteristics, such as reactive plasma species and temperatures, are determined by means of optical emission spectroscopy (OES), laser scattering, and infrared (IR) camera imaging whereas the fluid dynamics are analyzed using computational fluid dynamics (CFDs) and Schlieren imaging. The obtained promising results clearly show the flexibility and adaptability of the MPPJ3 device for polymer processing applications.

Corelease of Genotoxic Polycyclic Aromatic Hydrocarbons and Nanoparticles from a Commercial Aircraft Jet Engine - Dependence on Fuel and Thrust.

Jet engines are important contributors to global CO2 emissions and release enormous numbers of ultrafine particles into different layers of the atmosphere. As a result, aviation emissions are affecting atmospheric chemistry and promote contrail and cloud formation with impacts on earth's radiative balance and climate. Furthermore, the corelease of nanoparticles together with carcinogenic polycyclic aromatic hydrocarbons (PAHs) affects air quality at airports. We studied exhausts of a widely used turbofan engine (CFM56-7B26) operated at five static thrust levels (idle, 7, 30, 65, and 85%) with conventional Jet A-1 fuel and a biofuel blend composed of hydro-processed esters and fatty acids (HEFA). The particles released, the chemical composition of condensable material, and the genotoxic potential of these exhausts were studied. At ground operation, particle number emissions of 3.5 and 0.5 × 1014 particles/kg fuel were observed with highest genotoxic potentials of 41300 and 8800 ng toxicity equivalents (TEQ)/kg fuel at idle and 7% thrust, respectively. Blending jet fuel with HEFA lowered PAH and particle emissions by 7-34% and 65-67% at idle and 7% thrust, respectively, indicating that the use of paraffin-rich biofuels is an effective measure to reduce the exposure of airport personnel to nanoparticles coated with genotoxic PAHs (Trojan horse effect).

Study on the combination of the annular jet pump and static mixer to improve the fluid‐carrying capacity of gas wells

AbstractAiming at the problem that the suction chamber of the gas‐driven jet pump has insufficient mixing of the power gas and the sucked fluid leading to efficiency reduction, this study proposes to effectively combine the static mixer with the annular jet pump and design a new type of annular jet pump and apply it to the gas wells to improve the fluid recovery capacity. Numerical simulations based on the gas–liquid two‐phase flow model are carried out for a conventional annular jet pump (CAJP) and a new annular jet pump (NAJP). The reliability of the simulation results is verified by gas–liquid two‐phase flow experiments, and the differences between the two in terms of velocity, pressure loss, and turbulent kinetic energy are analyzed. Meanwhile, the validity of NAJP is verified, and the effects of different structures such as static mixer torsion angle, suction chamber angle, and area ratio on the performance of NAJP are analyzed. The results show that NAJP enhances the degree of mixing between the sucked fluid and the power gas through the cyclonic effect created by the static mixer compared with CAJP. It results in a 10.6% year‐on‐year increase in the velocity of the sucked fluid, a 3% year‐on‐year increase in the pressure drop, and a 12.2% year‐on‐year increase in efficiency. NAJP can significantly improve the fluid‐carrying performance. With a mixer angle of 210°, a suction chamber angle of 21°, and an area ratio of 1.77, the NAJP achieves an efficiency of 39.7%, which is a year‐on‐year increase of 7.3% compared to the structure under the same conditions before optimization. This study lays a foundation for the determination of the optimal design scheme of the annular jet pump and at the same time can provide theoretical and technical support for researchers in related fields.

Overall performance of Ni-Co-WC nanocomposite coatings prepared by ultrasonic vibration-assisted scanning jet electrodeposition

To obtain a high-performance Ni-Co-WC nanocomposite coating on 45# steel, this work proposed a novel ultrasonic vibration-assisted scanning jet electrodeposition and used the range of WC nanoparticles concentration (3-12 g/L) in the electrolyte as the key variable in this study. Through harmonic response analysis, a 31 kHz frequency ultrasonic transducer was selected as the vibration source to achieve better vibration effects. The type of current mode that we employed was DC mode. The influence of ultrasonic vibration and the concentration of WC nanoparticles in the electrolyte on the surface morphology, micro-texture, microhardness, adhesion, and corrosion resistance of the nanocomposite coating were investigated by using SEM, XRD, Vickers microhardness tester, scratch tester and electrochemical workstation respectively. Compared to conventional scanning jet electrodeposition, the results indicated that the ultrasonic vibration improved the surface morphology, mechanical properties, and corrosion resistance of the coating, with the hardness increased by 15.9 % and the adhesion strength increased by 76.1 % as well as the corrosion current density decreased by 13.0 %. When the WC concentration in the electrolyte was 6 g/L, the Ni-Co-WC nanocomposite coating prepared by ultrasonic vibration-assisted composite scanning jet electrodeposition exhibited the best surface quality and properties. The microhardness of the coating was the highest at 590 HV, the adhesion strength was the largest at 33.4 N and the corrosion current density was as low as 4.104 μA·cm−2. Compared with the WC concentration of 3 g/L, when the WC concentration was 6 g/L, the hardness increased by 7.8 %, the adhesion strength increased by 41.5 % whereas the corrosion current density decreased by 30.6 %. In addition, molecular dynamics simulation was employed to calculate the effect of WC content in the coating on the binding energy between the coating and the substrate. The simulation results confirmed that the adhesive strength between the composite coating and substrate was directly proportional to the WC content in the composite coating. Therefore, this research is of great significance for the protection of offshore platform support structure materials and the improvement of their service life.

Understanding the impact of molecular structure on the formation of stable intermediates during the pyrolysis of monoalkylated cyclohexanes in a shock tube

Alkylcyclohexanes are common constituents of conventional jet fuels and are expected to be a vital molecular subclass in next-generation, sustainable aviation fuels (SAFs). In an effort to advance the current understanding of the combustion chemistry of these species at engine-relevant conditions, we measured the time-resolved evolution of key stable intermediates during the pyrolysis of cyclohexane (CH) and four monoalkylated cyclohexanes: methylcyclohexane (MCH), ethylcyclohexane (ECH), propylcyclohexane (PCH), and butylcyclohexane (BCH), using laser absorption spectroscopy (LAS) in a shock tube. These experiments were conducted using 2 % Fuel/Argon test mixtures at a nominal pressure of 2 atm over the temperature range 1150–1530 K. Simultaneous tracking of the mole fraction time histories of methane, ethylene, and larger alkenes (>C2) provided new, valuable insight into the high-temperature reactivity of the five fuels studied. Studying all five fuels under similar test conditions enabled us to observe clear trends in the yields of different pyrolysis products with varying molecular structure, specifically increasing the number of carbon atoms in the alkyl chain. The fuel structure effects investigated in this work are instrumental in characterizing the pyrolysis product distribution, and thereby the overall combustion behavior of cyclohexane derivatives with longer (>C4) alkyl chains. We believe the multi-wavelength speciation data presented in this work can significantly contribute towards the development of robust, simplified, and fuel-specific kinetic models for monoalkylated cyclohexanes.

Cost-benefit analysis of using sustainable aviation fuels in South America

The sustained growth of global aviation emissions has highlighted the urgent need for using Sustainable Aviation Fuels (SAFs) to replace traditional aviation fuels to mitigate emissions. SAFs can potentially reduce greenhouse gas emissions by 50%–90% compared to conventional jet fuels. This paper collected aviation emissions data from South American routes between 2019 and 2021, and the GWP100 method was used to convert CH4 and N2O emissions into CO2 equivalents. Additionally, emissions from the South American route between 2023 and 2070 were predicted, as well as the amount of subsidy required to promote the use of SAFs under four different scenarios. The result shows that adopting SAFs could reduce approximately 69.3 million to 113.53 million tons of CO2-equivalent emissions in South America by 2070. However, the South American aviation industry will likely embrace using SAFs only if the carbon trading price exceeds 0.273 times the difference between SAFs and jet fuel prices.

Cycloalkane-Rich Sustainable Aviation Fuel Production via Hydrotreating Lignocellulosic Biomass-derived Catalytic Fast Pyrolysis Oils

Sustainable aviation fuel (SAF) produced from lignocellulosic biomass is emerging as an ideal alternative to conventional jet fuel for aviation sector decarbonization. Catalytic fast pyrolysis (CFP) can convert lignocellulosic biomass...

Experimental investigation and modeling of boundary layer flashback for non-swirling premixed prevaporized n-propanol/air and /isopropanol/air flames

The idea of utilizing lean, premixed and prevaporized (LPP) combustion could be a step towards sustainable aviation in the future, with the absolute absence of soot particles and very low nitrogen oxide emissions. However, premixing with compressed hot air presents a challenge for both conventional jet fuel and synthetically produced sustainable aviation fuel (SAF) due to self-ignition and flashbacks. Our group is thus seeking LPP-compatible advanced sustainable aviation fuels, which are evaluated based on their flashback propensity. Preliminary studies indicate that short-chain alcohols, with their higher ignition delay times and lower flame velocities, may be appropriate for LPP combustion concepts. In this study, the isomers of propanol, n-propanol, and isopropanol, are the first representatives of the short-chain alcohols to be investigated experimentally and numerically with respect to their flame stability limits. The experimental determination of stability limits for n- and isopropanol/air premixed flames was conducted on a generic, non-swirled atmospheric burner for an equivalence ratio range of 0.82 to 1.11. A fully automated measurement procedure was used to generate 119 measurement points with Reynolds numbers in the range from 1430 to 2750. The influence of the positional isomerism and of the preheat temperature (422 K, 446 K and 466 K) of the unburned mixture are investigated. A clear influence of the isomeric fuel structure is found. A theoretical analysis shows that it can be related to the different laminar flame speed and laminar flame thickness of the isomers. Moreover, a detailed analysis shows that the critical velocity gradient concept to describe boundary layer flashback is well usable with a Péclet number model.

A Review Study of Sweeping and Normal Impingement Jets

This review focuses on the experimental and numerical studies of sweeping impingement jets that serve in cooling of hot surfaces. It is known that the impinging jets produce high-localized heat transfer coefficient. The sweeping jet covers a wider area on a hot target to improve the heat transfer rate, they could be used to increase the cooling rate of the impingement surface by disturbing the boundary layer. To display a readable survey, the current review was partitioned to four groups based on engineering configurations. The review shows that the sweeping nozzle gives better efficiency in heat transfer, improved Nusselt number and uniform target surface temperature, compared with the conventional normal jets. The current review reveals that the sweeping-jet mechanism can be achieved either by fluidic oscillator or by exciting a flexible wall forming an oscillating jet. Most of the fluidic oscillator researches are conducted experimentally (27%), while the researches that use flexible wall are about 24%.

Numerical Modeling of Chemical Kinetics, Spray Dynamics, and Turbulent Combustion towards Sustainable Aviation

With growing interest in sustainable civil supersonic and hypersonic aviation, there is a need to model the combustion of alternative, sustainable jet fuels. This work presents numerical simulations of several related phenomena, including laminar flames, ignition, and spray flames. Two conventional jet fuels, Jet A and JP-5, and two alternative jet fuels, C1 and C5, are targeted. The laminar burning velocities of these fuels are predicted using skeletal and detailed reaction mechanisms. The ignition delay times are predicted in the context of dual-mode ramjet engines. Large Eddy Simulations (LES) of spray combustion in an aeroengine are carried out to investigate how the different thermodynamic and chemical properties of alternative fuels lead to different emergent behavior. A novel set of thermodynamic correlations are developed for the spray model. The laminar burning velocity predictions are normalized by heat of combustion to reveal a more distinct fuel trend, with C1 burning slowest and C5 fastest. The ignition results highlight the contributions of the Negative Temperature Coefficient (NTC) effect, equivalence ratio, and hydrogen enrichment in determining ignition time scales in dual-mode ramjet engines. The spray results reveal that the volatile alternative jet fuels have short penetration depths and that the flame of the most chemically divergent fuel (C1) stabilizes relatively close to the spray.

A bibliometric analysis on sustainable aviation fuels: core technologies, challenges and trends

International initiatives such as the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) have set goals for the complete de-carbonization of international aviation in this century. It motivated increasing numbers of Sustainable Aviation Fuel (SAF) research projects. The objective of this paper is to provide an overview on SAF research to point one to its foundations and recent advances. Data from the Web of Science database was collected and investigated. Important papers, cooperation networks, textual, productivity and trends analysis is provided. The most productive countries are in the global north, led by the United States and China. Big developing nations such as India and Brazil need to improve. The future of a sustainable aviation sector is heading in the direction of replacement of conventional jet fuel by synthetic hydrocarbon fuels by the end of the century. But there are still doubts about its viability both from the environmental and practical aspects, as there are concerns about feedstock availability and life cycle emissions. Fischer-Tropsch Synthesis, Alcohol-to-Jet and Hydroprocessing of Esters and Fatty Acids appear as the main SAF technologies for drop-in replacements. Longer term prospects are for the development of more efficient aircraft designed for renewables and non-hydrocarbon energy sources.

Life‐cycle analysis of sustainable aviation fuel production through catalytic hydrothermolysis

AbstractCatalytic hydrothermolysis (CH) is a sustainable aviation fuel (SAF) pathway that has been recently approved for use in aircraft fuel production. In alignment with broader sustainable aviation goals, SAF production through CH requires a quantitative assessment of carbon intensity (CI) impacts. In this study, a current‐day life‐cycle analysis (LCA) was performed on SAF produced via CH to determine the CI. Various oily feedstocks were considered, including vegetable oils (soybean, carinata, camelina and canola) and low‐burden oils and greases (corn oil, yellow grease and brown grease). Life‐cycle inventory data were collected on all processes within the CH LCA boundary: feedstock cultivation and/or collection, preprocessing, hydrothermal cleanup and CH, biocrude refining, fuel transportation and end use through combustion. Baseline results show that the CH‐produced SAF can be generated with CI reductions ranging from 48 to 82% compared with conventional jet fuel. Modest improvements to CI can be achieved through incremental changes to the brown grease CH process, such as relaxing the dewatering specification and implementing renewable natural gas and electricity, which could decrease the CI from 22.9 to 7.9 g CO2e/MJ. Total CH fuel production potential was also assessed on the basis of current or near‐future feedstock availability and CI. The total biofuel production potential of CH (SAF and renewable fuel co‐products) in the US sums to approximately 3487 million gallons per year, with 97% of these volumes having a CI below 50% of that for petroleum jet fuel. The study shows that from an LCA perspective, CH offers a viable SAF pathway that is comparable with existing SAF pathways like hydroprocessed esters and fatty acids.

Impact of bioenergy feedstock carbon farming on sustainable aviation fuel viability in the United States.

Biomass-derived sustainable aviation fuel holds significant potential for decarbonizing the aviation sector. Its long-term viability depends on crop choice, longevity of soil organic carbon (SOC) sequestration, and the biomass-to-biojet fuel conversion efficiency. We explored the impact of fuel price and SOC value on viable biojet fuel production scale by integrating an agroecosystem model with a field-to-biojet fuel production process model for 1,4-dimethylcyclooctane (DMCO), a representative high-performance biojet fuel molecule, from Miscanthus, sorghum, and switchgrass. Assigning monetary value to SOC sequestration results in substantially different outcomes than an increased fuel selling price. If SOC accumulation is valued at $185/ton CO2, planting Miscanthus for conversion to DMCO would be economically cost-competitive across 66% of croplands across the continental United States (US) by 2050 if conventional jet fuel remains at $0.74/L (in 2020 US dollars). Cutting the SOC sequestration value in half reduces the viable area to 54% of cropland, and eliminating any payment for SOC shrinks the viable area to 16%. If future biojet fuel prices increase to $1.24/L-Jet A-equivalent, 48 to 58% of the total cultivated land in the United States could support a more diverse set of feedstocks including Miscanthus, sorghum, or switchgrass. Among these options, only 8-14% of the area would be suitable exclusively for Miscanthus cultivation. These findings highlight the intersection of natural solutions for carbon removal and the use of deep-rooted feedstocks for biofuels and biomanufacturing. The results underscore the need to establish clear and consistent values for SOC sequestration to enable the future bioeconomy.