Traditional Jet Research Articles

Modeled economic potential for Eucalyptus spp. production for jet fuel additives in the United States

Feedstock price and availability remain a barrier to adoption of cellulosic biofuels. Eucalyptus spp., can produce an energy-dense terpene suitable for high-density synthetic hydrocarbon-type fuel (grade JP-10) production in addition to cellulosic-based feedstock for traditional jet fuels (e.g., grade Jet A) and gasoline. This study modeled economic potential for Eucalyptus to fulfill US fuel markets. Cold-tolerant Eucalyptus was simulated in an annual coppice system for maximized leaf production. Results of the lowest simulated price ($110 t−1) show that within 10 years, there is potential to produce 204 million L yr−1 of fuel, including 51 million L yr−1 of JP-10-type fuel, 75 million L yr−1 of Jet A type fuel, and 77 million L yr−1 of gasoline. These quantities of fuel could be valued at approximately $500 million (USD), with feedstock costs totaling approximately $100 million (USD). Longer-term markets (to 20 years) or higher priced (to $220 t−1) scenarios show potential for more production. Research to determine potential for genetic improvement, delivered fuel costs, and biorefinery siting near existing infrastructure is recommended.

Performance and Emissions of Drop-In Aviation Biofuels in a Lab-Scale Gas Turbine Combustor

Abstract There is a growing need for drop-in biofuels for gas turbines for enhanced energy security and sustainability. Several fuels are currently being developed and tested to reduce dependency on fossil fuels while maintaining performance, particularly in the aviation industry. The transition from traditional fossil fuels to sustainable biofuels is much desired for reducing the rapidly rising CO2 levels in the environment. This requires biofuels to be drop-in ready, where there are no adverse effects on performance and emissions upon replacement. In this study, the performance and emissions of four different aviation drop-in biofuels were evaluated. They include UOP HEFA-SPK, Gevo ATJ, Amyris Farnesane, and SB-JP-8. These aviation biofuels are currently being produced and tested to be ready for full or partial drop-in fuels as the replacement of traditional jet fuels. The characteristic performance of each fuel from the prevaporized liquid fuels was performed in a high-intensity (20 MW/m3-atm) reverse flow combustor. The NO emissions showed near unity ppm levels for each of the fuels examined with a minimum at an equivalence ratio of ∼0.6, while CO levels were in the range of 1000–1300 ppm depending on the fuel at an equivalence ratio between 0.75 and 0.8. For an equivalence ratio range between 0.4 and 0.6, NO and CO emissions remained very low (between 1–2 ppm NO and 2400–2900 ppm CO) depending on the fuel. The examined biofuels did not show any instability over a wide range of equivalence ratios from lean to near stoichiometric condition. These results provide promising results on the behavior of these drop-in aviation biofuels for use in high-intensity gas turbine combustors providing stability and cleaner performance without any modification to the combustor design.

A Study on Bio-Diesel and Jet Fuel Blending for the Production of Renewable Aviation Fuel

Aviation industry is considered one of the contributors to atmospheric CO2emissions. It is forced to cut off carbon dioxide emission starting 2020. Current trends in bio-jet production involve mega projects with million dollars of investments. In this study, bio-jet fuel production by blending bio-diesel with traditional jet fuel at different concentrations of bio-diesel (5, 10, 15, 20 vol. %) was investigated. This blending technique will reduce bio-jet production cost compared to other bio-jet techniques. Bio-diesel was originally produced by the transesterification of non-edible vegetable oil (renewable sources), so, its blend with jet fuel will has a reduced carbon foot print. The blend was tested to ensure that the end product will meet the ASTM D1655 international specifications for Jet A-1 and Jet A and can be used in aircrafts.Available data on biodiesel blending with jet fuel in the literature is not consistent, there are many contradictory results. Hence, more investigations are required using locally available feedstocks. The main physicochemical properties for Jet A-1 and Jet A according to ASTM D1655 were tested to check if the blend will be compatible with existing turbojet engine systems. Different tests were conducted; vacuum distillation, smoke point, kinematic viscosity, density, flash point, total acidity and freezing point. In addition, heating value of the blend was calculated. The result was then compared with calculated value using blending indices available in the literature. Blending indices were able to predict the laboratory measured specifications for the studied blends.It was found that only 5% bio-diesel- 95% jet fuel blend (B5) meets ASTM standard for Jet A. Hence, biodiesel can be safely used as a blend with fossil-based jet for a concentration of up to 5% without any change in the ASTM specifications. Freezing point is the most important constrain for this blending technique. Higher blends of biodiesel will cause the bio-jet blend to fail ASTM specifications. In general, blending technique will reduce the cost impact that may have been incurred due to change in infrastructure when using other production techniques.

Theoretical and experimental study on jet formation and penetration of the liner loaded by electromagnetic force

Jet formation driven by strong magnetic field adopts the electromagnetic force to collapse the liner and breaks through the traditional jet forming mode of shaped charge, which relies on explosive. The influence of material strength on the liner deformation under low current is considered in this work to study the formation characteristics of the jet. Combined with the loading circuit, the jet formation and critical yield current (CYC) models are established. Subsequently, the CQ-4 device with 0.115 MJ energy is used to carry out electromagnetic loading experiments on the conical liners with a diameter of 10 mm and thickness of 1, 1.5, and 2 mm. The static penetration test method was used to test the jet power. The liners were all collapsed, and effective jets were formed by liners with 1 mm and 1.5 mm thickness. The depth of penetration (DOP) to the aluminum and steel targets were 30 mm and 12.5 mm, respectively. However, the 2 mm-thick liner almost did not have the ability to penetrate the steel target. The formation, movement, stretching, and penetration of the jets were calculation by theory and simulation. Results are in good agreement with the experiments. In the scope of this paper, the velocity and power of the jet increase with the decrease in liner thickness. The jet formation under theoretical calculation with and without material strength are compared and analyzed. The results indicated that the material strength cannot be ignored when the loading current is small. The formation characteristics of the liners under different loading currents are also calculated theoretically. The formation of the different liner elements under various currents are also calculated theoretically, and the peak current to CYC ratio is proposed to judge the formation state of the jet.

Effects of modulation position on the impact performance of mechanically modulated pulsed water jet

In this study, experiments were conducted to investigate the effects of modulation position on the impact performance (axial impact pressure, erosion radius, and erosion depth) of mechanically modulated pulsed water jet (MPWJ). The frequency of MPWJ was kept constant at 20 Hz, and the supply pressures were varied from 10 MPa to 25 MPa. The results showed that both the disc-to-nozzle distance and disc-to-target distance influenced the impact pressures of MPWJ. There was an optimal ratio of disc-to-nozzle distance to disc-to-target distance for achieving maximum impact pressure. Compared with traditional jet, there were extra radial grooves on the eroded samples. Under the same standoff distance, the reduction of disc-to-nozzle distance caused an increase in the radius of erosion crater. The depth of the erosion crater increased first and then decreased with the increasing ratio of disc-to-nozzle distance to disc-to-target distance. The results of this study provide useful information to determine appropriate parameters to improve the processing capability and coverage of MPWJ during material processing.

Stacked-cup multiwall carbon nanotubes as components of energy-intensive suspension jet fuels

Objectives. The addition of high-density carbon materials to jet fuels can lead to a significant increase in the volumetric energy of the fuel combustion. The purpose of the current study was to thermodynamically analyze the possibility of obtaining model hydrocarbon fuels from toluene and T-1 using stacked-cup multiwall carbon nanotubes (MWCNTs). Methods. Bomb combustion calorimetry was used to define the combustion energy of the MWCNTs in the crystalline state. The temperature dependence of the MWCNTs’ heat capacity in the range 5–370 K and the fusion parameters were estimated using low-temperature adiabatic calorimetry. The physical density of MWCNTs was measured using the pycnometric method. The sedimentation stability of the mixtures of MWCNTs with liquids was determined using centrifugation at 7000 g. The calculations were carried out in MS Excel. Results. The energy and enthalpy of combustion of a technical sample of MWCNTs in the crystalline state were determined. Based on the smoothed heat capacity values, the standard thermodynamic functions (enthalpy, entropy, and Gibbs reduced energy) of MWCNTs in the crystalline state were obtained in a temperature range of 0–2000 K. The extrapolation of the MWCNTs’ heat capacity was carried out at a temperature of up to 2000 K using the heat capacity of crystalline graphite. It has been established that mixtures of MWCNTs with liquids containing more than 33 mass % of MWCNTs are stable during centrifugal sedimentation at 7000 g. For the toluene–MWCNTs and fuel T-1–MWCNTs model systems, the specific and volumetric combustion energies, the adiabatic combustion temperatures, and the conditional final maximum speed of the model rockets with fuel of various compositions were also calculated. Conclusions. The thermodynamic analysis showed that the addition of MWCNTs can significantly increase the volumetric energy intensity of traditional jet fuels, which can in turn improve the operational characteristics of drones and rockets.

Higgs production at NNLL\u2032+NNLO using rapidity dependent jet vetoes

The rapidity-dependent jet veto observables {mathcal{T}}_{Bj} and {mathcal{T}}_{Cj} provide a tight jet veto at central rapidity, gradually transitioning to a loose veto at forward rapidities. They divide the phase space into exclusive jet bins in a different way to the traditional jet veto observable pT j, and are advantageous to use under harsh pile-up conditions. We obtain predictions for the 0-jet gluon-fusion (ggF) Higgs cross section using both of these veto observables at NNLL′+NNLO, and compare these predictions to the prior state-of-the-art of NLL′+NLO. A significant reduction in perturbative uncertainty is observed going from NLL′+NLO to NNLL′+NNLO, with the NNLL′+NNLO predictions lying inside the uncertainty band of the NLL′+NLO predictions. We also investigate the relative sensitivities of ggF Higgs cross sections with {mathcal{T}}_{Bj} , {mathcal{T}}_{Cj} and pT j jet vetoes to underlying event and hadronisation effects using an NLO+parton shower calculation. We find that the cross sections with {mathcal{T}}_{Bj} and {mathcal{T}}_{Cj} vetoes have a reduced sensitivity to underlying event and hadronisation effects compared to that with a pT j veto.

The conversion of biomass into renewable jet fuel

Producing renewable jet fuels from solid waste contributes greatly on circular economy with respect to the energy, environment and economics. The feedstock sources are resolved, the solid wastes are re-used, the pollution from aircrafts are reduced and the air energy is renewed. In this study, the rice husk biomass, which has been a headache agriculture waste in Taiwan, was turned into products similar to traditional jet fuel through fluidized bed fast pyrolysis, hydro-processing and hydro-cracking/isomerization, in which significant increases in normal alkanes, iso-alkanes and cycloalkanes were found. The final product from hydro-cracking/isomerization contained appropriate amount of normal, iso-, and cyclo-alkanes, which made it suitable to be the replacement for jet fuel.

Decision Support System for Selecting Sustainable Alternatives to Conventional Jet Fuel: Impact of Emissions, Production Costs and Carbon Pricing

The United States Environmental Protection Agency (EPA) in June 2015, took a step toward regulating carbon emissions from airlines, following an assessment that airlines contribute to climate change. On July 25, 2016, the final endangerment finding (Note 1) under section 231(a) (2) (A) of the Clean Air Act for aviation emissions was issued by the EPA. The European Union had issued a similar finding previously and had proposed implementing an emission trading scheme in which the airlines would be required to participate in a cap and trade scheme for emissions from jet fuel. Traditional jet fuel is derived from petroleum, whose price is volatile and depends on geopolitical stability. Fuel burn is a significant cost for airlines and affects their profitability and value. Fuel burn is also a significant source of greenhouse gas emissions. An investigation of alternatives to jet fuel and switching from conventional jet fuel based on varying emission profiles, production costs and varying carbon prices is therefore timely. We use a simple decision support system to examine the link between the life-cycle greenhouse gas emissions of a range of fuels, economic costs of production and varying carbon prices. This analysis should be of interest to regulators, traders, risk managers and executives in the airline industry as well as practitioners of sustainability management.

Drying of moist cookie doughs with innovative slot jet reattachment nozzle

The drying of moist porous media, such as pulp, paper and food products, is one of the most energy intensive processes in industry. Many convective drying processes utilize impinging jet nozzles. There have been many efforts to improve the transport characteristics of impinging jet nozzles. Utilizing the innovative slot jet reattachment (SJR) nozzle is an approach to make the convective drying process more efficient. This is mainly because SJR nozzles overcome the high flow rate constraint associated with the traditional slot jet (SJ) nozzle. In this paper, the drying characteristics of the SJR nozzle with exit angles of +20˚ and +45˚ are experimentally investigated for a snack cookie. The results are compared with those of SJ nozzle based on three criteria: identical air mass flow rate, fluid flow power, and peak exerted surface pressure. An IR camera is used to capture the sample surface temperature distribution during the drying process. The results indicate that up to 57% reduction in drying time to reach 2% dry basis moisture content level is achieved with SJR + 20° nozzle compared to that of SJ nozzle based on the equal surface peak pressure criterion.

Compressed Air-Film Encircling Jet Electrodeposition with High Deposition Accuracy

To improve the deposition accuracy and surface quality of the deposited micro-features, a novel compressed air-film encircling Jet ECD was proposed. In the proposed Jet ECD, a high-speed compressed air-film is coaxially encircling the impinging electrolytic jet. Numerical model describing the coupled field of electric field and flow field was established, and some auxiliary observations and measurement experiments were conducted to investigate the distribution characteristics of electric field and hydrodynamics characteristics in the concerned regions as well as the change of the electrolyte jet diameter. And the effect of air-film formation parameters and hydrodynamic parameters of the electrolyte jet on the electrodeposition behaviors during forming patterns and high aspect ratio micro-features were studied. Deposition accuracy and surface quality of the microstructures fabricated by the compressed air-film encircling Jet ECD were evaluated. It was demonstrated that, compared with the traditional Jet ECD, the proposed Jet ECD has a higher deposition accuracy and faster deposition rate (up to 1 μm s−1) as well as better surface quality. In addition, the newly developed Jet ECD has an admirable additive manufacturing ability and a 370 ± 3 μm-diameter smooth column with the aspect ratio of about 20 was successfully manufactured.

Passenger perceptions on sustainable propulsion systems: which factors mediate or moderate the relationship

The purpose of these studies was to examine how the type of propulsion system impacted the willingness to fly in a hypothetical scenario. Using a sample of 624 participants from the USA across two studies, it was found, in general, that participants were most willing to fly using traditional jet fuel or a biofuel followed by battery/electric and then solar-powered aircraft. There were no significant differences based on participant gender, any significant interactions nor any significant mediators between the type of propulsion and the willingness to fly. Still, familiarity with sustainability, willingness to pay for sustainability, and environmental commitment were found to be significant moderators. In cases where participants had high levels of the three moderating variables, they were significantly more willing to fly using sustainable propulsion systems than compared to low levels of the moderating variables. The study concludes with a discussion of these findings and the practical applications of this research.

Passenger perceptions on sustainable propulsion systems: which factors mediate or moderate the relationship

The purpose of these studies was to examine how the type of propulsion system impacted the willingness to fly in a hypothetical scenario. Using a sample of 624 participants from the USA across two studies, it was found, in general, that participants were most willing to fly using traditional jet fuel or a biofuel followed by battery/electric and then solar-powered aircraft. There were no significant differences based on participant gender, any significant interactions nor any significant mediators between the type of propulsion and the willingness to fly. Still, familiarity with sustainability, willingness to pay for sustainability, and environmental commitment were found to be significant moderators. In cases where participants had high levels of the three moderating variables, they were significantly more willing to fly using sustainable propulsion systems than compared to low levels of the moderating variables. The study concludes with a discussion of these findings and the practical applications of this research.

Research on the performance of sidewall perforated plate air supply system that suitable for prefabricated buildings

Taking the rural prefabricated residential building as research object, prefabricated sidewall partitioned perforated plate air supply model and traditional jet air supply model were established respectively. Then, CFD commercial software was used to simulate the temperature field, velocity field, formaldehyde concentration of indoor air-flow distribution of the two air supply model that mentioned above. Simulation results show that in the indoor breathing zone, the valuation index of prefabricated sidewall partitioned perforated plate air supply system, such as the velocity non-uniformity coefficient, air diffusion performance index, ventilation efficiency are entirely superior to the traditional jet air supply system. Moreover, the maximum vertical temperature gradient and maximum horizontal temperature gradient of the prefabricated sidewall partition perforated plate air supply system were also small which means the new air supply system could satisfy the indoor air quality and human thermal comfort requirements.

Numerical investigation on behaviors of interlaced jets and their interaction with bath in BOF steelmaking

The jet behavior of interlaced multiple nozzles and the impingement of multiple jets onto the surface of the molten metal bath in a steelmaking converter are numerically studied. The interlaced jet hydrodynamic behaviors such as jet profile, coalescence characteristics, and dynamic parameter distributions penetration depth and impact area, as well as time-dependent evolution of liquid bath are discussed. The results are compared with traditional nozzles. It is found that the single nozzle characteristics of staggered jet are similar to those of traditional jet. However, two sets of staggered nozzles with different flow rate and inclination angle having a less disturbance flows, cause weaker coalescence of the jets and larger area surrounded by isovelocity in the molten pool. In the initial stage of the interaction between the interlaced nozzles and the molten pool, the “low stirring zone” is more likely to concentrate in the outer side near the furnace wall than in the center of the molten pool. Two cavities, one deep and one shallow, are formed on the bath surface. The average depth of the two cavities is similar to traditional nozzles, and the diameter of the cavity is increased by about 11% compared to traditional nozzles.

Mechanical properties and corrosion resistance of Ni-Co-SiC composite coatings by magnetic field-induced jet electrodeposition

Ni-Co alloys and Ni-Co-SiC composite coatings were manufactured by magnetic field-induced jet electrodeposition. The microstructure and nanoparticles distribution of the coatings were characterized by field emission scanning electron microscopy, energy dispersive X-ray spectrometry, and X-ray diffraction. The surface roughness, adhesion and corrosion resistance of the coatings were measured using a three-dimensional profilometer, a scratch tester, and an electrochemical workstation. The cellular protrusions on the composite coatings decreased with the addition of nano-SiC particles. However, a large number of small spherical structures grew into large cellular protrusions with an extremely high SiC concentration under traditional jet electrodeposition. The composite coatings under magnetic field-induced jet electrodeposition showed a uniform growth and no protrusions, the nano-SiC particles were also uniformly distributed. The Ni-Co-SiC composite coating exhibited a single-phase solid solution structure, and its adhesion increased to 33.2 N, which was 2.65 times that of the Ni-Co alloy coating. The corrosion current density of the composite coating was 4.768 μA cm−2, which was sufficient to protect sintered NdFeB magnets.

A supersonic target jet mill based on the entrainment of annular supersonic flow.

Jet mill is an apparatus that produces superfine powder and is widely used in various industries. In this work, a new supersonic target jet mill based on aerodynamic theory is presented according to the flow field of a traditional jet mill. An annular supersonic flow produced by an annular converging-diverging nozzle is used to entrain the central particle flow by the shear mechanism in this new supersonic target jet mill. Then, the particle beam concentrating in the flow center impacts the target with high kinetic energy after the entrainment of the supersonic flow. An apparatus of the annular supersonic target jet mill was created to validate the theoretical design. Two types of experiments were implemented to estimate its performance. The validation experiments confirmed that the gas speed in the collision chamber was approximately 600 m/s and the supersonic flow could deliver a kinetic energy of approximately 180 J/s to the particles. The particle size reduction of boroncarbide (B4C) and silica (Si) in the collision tests showed that the accelerated particles concentrated in the supersonic flow center collided on the targets precisely with high collision energy.

Preparation of Ni-SiC composite coatings by magnetic field-enhanced jet electrodeposition

To improve the effective working life of sintered NdFeB magnets, Ni-SiC composite coatings were prepared on NdFeB by magnetic field-enhanced jet electrodeposition. It was found that the influence of the magnetic field on the ions in the electrolyte improved the edged effect that is most likely to occur in traditional jet electrodeposition, accelerated the mass transfer of ions, and improved the coating morphology, as compared with Ni-SiC prepared by traditional jet electrodeposition. The microstructure and nanoparticle content of the coatings was characterized by field emission scanning electron microscopy (FESEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The coating microhardness, adhesion and corrosion resistance were tested by a microhardness instrument, scratch tester and electrochemical workstation, respectively. The results show that the magnetic field enhanced jet electrodeposition caused a decrease in defects in the Ni-SiC coating surface and an increase in the flatness. When the nano-SiC particle concentration was 3 g/L, the nano-SiC content in the coating increased to 3.27%, which is higher than the 2.13% of traditional jet electrodeposition. Also, the adhesion between the coating and the NdFeB was obviously improved and there was no gap, and the corrosion resistance was also further improved.

Refining drop-in jet fuel coupling GHGs reduction in LCA with airworthiness in aero-engine and aircraft

Abstract The current challenge of drop-in jet fuel should couple the reduction of GHGs emission in whole life cycle with economic competitiveness and achieving performance as same as traditional jet fuel without reducing safe service life in engine and aircraft. From the insight of GHGs reduction, the whole life cycle, including sustainable feedstock, refining process integration and low emission in combustion are optimized for reduction in energy input and emission output. From the insight of airworthiness in aero-engine and aircraft, a certification process is achieved by extracting safety criteria from the “history experience” of petroleum-based jet fuel as the source and to predict the aero-engine safety implications of alternative aviation fuels as the target by “similar analogy”. The critical key parameters have been extracted by fundamental process related with safety and performance on achieving the duty of engine in the whole flight envelop. Alternative jet fuel can be qualified for certifying drop-in jet fuel and accordingly confirm with identical safe service life in engine and aircraft by analogizing the boundaries of critical key parameters with petroleum-based jet fuel. The critical parameters thereof, including carbon distribution and classification as well as C/H ratio, can conduct directly for feedstock choice and refining process modification. Accordingly, a process of refining algae-based jet fuel was modified coupling the requirement of GHGs reduction in life cycle with airworthiness in aero-engine and aircraft. Based on process integration to connect upstream feedstock to downstream combustion outcomes of alternative jet biofuel and co-product, GHGs in fuel stage deduced further by co-product and nutrient recovery in spite of additional separation process.

Jet angularity measurements for single inclusive jet production

We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter a allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semiinclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.