Turbine Fuels Research Articles

A Rapid Analysis Method for Determination of Hydrocarbon Types in Aviation Turbine Fuel by Gas Chromatography-Mass Spectrometry.

A rapid analysis method for determination of hydrocarbon types in aviation turbine fuel was investigated in this study. A kind of reversible adsorption material packed as an unsaturated trap was used to separate saturated hydrocarbons and unsaturated hydrocarbons in the GC-MS system. No manual process or organic reagent was needed during the entire analysis process. The contents of 13 kinds of hydrocarbons, including paraffins, monocycloparaffins, dicycloparaffins, tricycloparaffins, monoolefins, cycloolefins, alkylbenzenes, CnH2n-8 aromatics, CnH2n-10 aromatics, naphthalenes, CnH2n-14 aromatics, CnH2n-16 aromatics, and CnH2n-18 aromatics were calculated by the characteristic mass fragments detected by MS with the modified matrices of ASTM D2425. The overall analysis time was less than 10 min. The precision of this test method has been conducted with 8 laboratories attended and 16 samples analyzed. The performance of this new method was demonstrated by comparing the results tested by ASTM D1319, ASTM D2425, and ASTM D6379. This rapid analysis method can provide hydrocarbon compositions of aviation turbine fuels or other liquid hydrocarbon samples within the same distillation range.

Development of a Method for Shape Optimization for a Gas Turbine Fuel Injector Design Using Metal-Additive Manufacturing

Abstract Adjoint shape optimization has enabled physics-based optimal designs for aerodynamic surfaces. Additive manufacturing (AM) makes it possible to manufacture complex shapes. However, there has been a gap between optimal and manufacturable surfaces due to the inherent limitations of commercial computational fluid dynamics (CFD) codes to implement geometric constraints during adjoint computation. In such cases, the design sensitivities are exported and used to perform constrained shape modifications using parametric information stored in computer aided design (CAD) files to satisfy manufacturability constraints. However, modifying the design using adjoint methods in CFD solvers and performing constrained shape modification in CAD can lead to inconsistencies due to different shape parameterization schemes. This paper describes a method to enable the simultaneous optimization of the fluid domain and impose AM manufacturability constraints, resolving one of the key issues of geometry definition for isogeometric analysis. Similar to a grid convergence study, the proposed method verifies the consistencies between shape parameterization techniques present within commercial CAD and CFD software during mesh movement as a part of the adjoint shape optimization routine. By identifying the appropriate parameters essential to a shape optimization study, the error metric between the different parameterization techniques converges to demonstrate sufficient consistencies for justifiable exchange of data between CAD and CFD. For the identified shape optimization parameters, the error metric to measure the deviation between the two parameterization schemes lies within the AM laser-powder bed fusion (L-PBF) process tolerance. Additionally, comparison for subsequent objective function calculations between iterations of the optimization loop showed acceptable differences within 1% variation between the modified geometries obtained using the two parameterization schemes. This method provides justification for the use of multiphysics guided adjoint design sensitivities computed in CFD software to perform shape modifications in CAD to incorporate AM manufacturability constraints during the shape optimization loop such that optimal designs are also additively manufacturable.

Quantifying isomeric effects: A key factor in aviation fuel assessment and design

Isomeric structural differences can profoundly influence hydrocarbon properties of importance to aviation turbine fuels. This is particularly true for alternative fuels that often contain fewer components than conventional fuels, making isomeric differences more impactful. The inability of standard analytical methods to distinguish isomers within a hydrocarbon family poses a significant challenge for the assessment and formulation of jet fuels. Such missing information leads to considerable uncertainties in model predictions used for fuel assessment, or aircraft and jet engine design. This work explores the influence of isomers on critical fuel properties using quantitative metrics from the chemical family, size, topology, and, particularly, branching. Isomeric property ranges within a given hydrocarbon class are deduced from a database study. The extent of these intra-hydrocarbon group property ranges is related to the change conferred via shifting to adjacent carbon numbers and dissimilar hydrocarbon families. This approach shows that isomeric information is as critical, if not more, for properties such as viscosity and freeze point, as carbon number and hydrocarbon class. This perspective significantly changes from the historical focus on carbon numbers and group-type analysis procedures. The correlations identified in this study can serve as a foundation for improving chemometrics. This, in turn, can enhance the accuracy of model-based property prediction and facilitate the design of new sustainable aviation fuels at a component level.

Investigation of turbulent heat transfer performance of aviation turbine fuel multi-wall carbon nanotube nanofluid

Nanofluid is a novel heat transfer fluid prepared by suspending high thermal conductivity nano-sized particles in conventional fluids (water, engine oil and ethylene glycol). Thermo-physical properties (Thermal conductivity, dynamic viscosity and specific heat) and turbulent heat transfer performanceof Aviation Turbine Fuel (ATF) based Multiwall Carbon Nanotube (MWCNT) nanofluid are investigated experimentally for particle volume concentrations of 0–1% and at mean fluid temperatures of 30οC and 50οC for a potential regenerative heat transfer application in semi-cryogenic liquid propellant rocket engine. The experimental results show that the heat transfer coefficient of the nanofluid increases with particle volume concentration, with a maximum enhancement at 1% particle volume concentration of approximately 23% and 50% observed at 30οC and 50οC respectively. Two different numerical modelling approaches (a single phase fluid model with enhanced thermo-physical properties and an Eulerian-Lagrangian model called the “discrete phase model”) are employed to simulate the experimental conditions. The predictions from both numerical modelling approaches are found to compare reasonably well with the experimental data. The enhanced heat transfer performance is expressed on an equal power penalty basis to clearely show the advantage of the nanofluid.

Investigation on combustion characteristics of acetone-butanol-ethanol/Jet A-1 mixture in a Swirl-stabilized combustor for its potential application in gas turbine engines

The projected growth of the energy demand due to domestic energy security, diversity of fuel supplies, and long-term fuel costs has attracted the scientific community to search for new alternative gas turbine fuels. Alcohol-based fuel could be a potential candidate for alternative fuel. The acetone-butanol-ethanol mixture with existing fossil fuels may be another prospect for alternative fuels that can drive gas turbine engines for clean combustion. However, well-suited alternatives to micro gas turbine fuel are still in the initial stages of growth. At present, the combustion characteristics of Jet A-1, ABE, and their mixtures in a swirl-stabilized combustor have been experimentally investigated. To compare the outcome of these fuels, visualization of true flame images, combustor exit temperature, and exhaust gas emission have been carried out. ABE1J9 has shown a 5 % reduction in pollutant emissions (e.g. CO2, NOx, compared to Jet A-1 whereas a 20 % reduction for the case of ABE3J7 and an almost 25–30 % reduction for the case of ABE5J5 are observed. Overall ABE blended fuel has shown better combustion performance in terms of the flame temperature profile, chemiluminescence, and pollutant emissions.

Effect of Aviation Turbine Fuel Exposure on Interlaminar and Inplane Shear Properties of Glass Fiber Reinforced Epoxy Composite

This study investigated the effect of aviation turbine fuel exposure on interlaminar and in-plane shear properties of E-glass/epoxy composite. The two types of test specimens, namely bare and resin-coated specimens with varying thicknesses as per the ASTM standard, were made out of E-glass/epoxy composite to evaluate their interlaminar and in-plane shear properties. These all types of specimens were immersed inside the aviation turbine fuel for two months and then afterward their effect on the reduction of mechanical properties like interlaminar and in-plane shear tests properties were experimentally investigated. Test results show that ATF fuel exposure has reduced the interlaminar shear strength by 10.04 %, 7.83 %, and 6.01 % for bare, with 0.1 mm and 0.2 mm resin coating, respectively. Similarly, in-plane shear strength was reduced by 14.75 %, 11.22 %, and 7.52 % for bare, with 0.1 mm and 0.2 mm resin coating, respectively, and in-plane shear modulus was reduced by 10.87 %, 8.94 %, and 6.52 % for bare, with 0.1 mm and 0.2 mm resin coating conditions as compared to as-received (without ATF exposure) specimens.SEM micrographs and results too showed that properties were reduced and indicated that the glass/epoxycomposite was resistive to fuel ingression. It was observed that bare specimens exhibited a reduction in shearproperties due to ATF ingression to the polymeric network and induced internal stresses, which not only degraded the matrix and fiber-matrix adherence but created micro-cracks too in the resin at interfaces. Resin-coated specimens limit fuel ingression, which has led to a reduction in properties.

Effect of Aviation Turbine Fuel Exposure on Tensile and Flexural Properties of Glass Fiber-Reinforced Epoxy Composite

Effect of Aviation Turbine Fuel Exposure on Tensile and Flexural Properties of Glass Fiber-Reinforced Epoxy Composite

Analysis of Gas Turbine Power Plant Production and Fuel Consumption

The main problem of gas turbine generating units operating in the simple cycle system is their relatively low thermal efficiency, which leads to large thermal energy losses. The current research aims to study the economic analysis of Kirkuk gas power plant. Field data of gas turbine unit for the year of 2019 were used. The results of the study showed that the cost of exported energy is higher than the cost of energy produced. The results showed a 23% increase in the cost of energy produced in summer compared to winter. A decrease in actual production compared to the planned production is observed by 12.8%, where the highest actual production for the month of March was 162,108 MW, while the planned was 186,000 MW. Also, the month of July witnessed a very low fuel consumption rate for natural gas compared to the rest of the months, where the average fuel consumption was 0.273 m3/kW, while the month of January has a high fuel consumption rate for natural gas compared to the rest of the year with average fuel consumption of 0.312 m3/kW. The rate of increase in fuel consumption between July and January was 14.2%, and the results also showed that the ratio of production to design capacity for January was the highest and amounted to 87%, and the highest efficiency reached 33%, while July was the lowest production rate in terms of design capacity, reaching 53% and efficiency of 29.8%.

Investigation of Water Droplet Size Distribution in Conventional and Sustainable Aviation Turbine Fuels

Investigation of Water Droplet Size Distribution in Conventional and Sustainable Aviation Turbine Fuels

Electrical conductivity of aviation turbine fuel (jet fuel) and its affecting factors: a case study

Electrical conductivity is an important characteristic for safe and economic handling of aviation turbine fuels which have the potential to accumulate static charges. Jet fuels are highly refined product with very low conductivity. To ensure safe fuel storage and distribution, Jet fuel specifications have been established specifying permissible levels of fuel conductivity. Static Dissipater Additive (SDA) or conductivity improver, is often added to fuel to achieve specification requirements. Controlling of SDA concentration via conductivity measurement is essential for commercial practice due to its surface active nature and anti-electrostatic properties All possible factors affecting the conductivity of jet fuel has been taken into account and described in this research article. The effect of 0.5 to 3.5 mg/l SDA on water separation characteristic (MSED) are also studied and presented.

Lignin-based jet fuel and its blending effect with conventional jet fuel

Sustainable aviation fuels (SAFs) must demonstrate specific physical and chemical properties as well as material compatibility (i.e., seal swell) to be used as aviation turbine fuels. Several alternative jet fuels incorporated in ASTM D7566 are comprised mainly of n/iso-alkanes and can only be blended up to 50 vol% due to material compatibility and density issues. Prior work illustrated the ability of cycloalkanes to replace the swelling potential of aromatics required for material compatibility. Here, we report the first archival documentation of a feedstock and chemical process to yield a product composition that could complement 5 existing SAF ASTM D7566 annexes. A lignin-based jet fuel (LJF) blend component is generated and composed of mostly C6–C18 mono, di, and tri-cycloalkanes. The neat LJF was blended with conventional jet fuel at 10 vol% (LJF blend) to simulate a potential qualification goal. Fuel properties critical to engine operability (ATSM D4054 Tier 3 & 4) were either predicted or experimentally tested based on the volume availability. All LJF-blended operability properties fall within the experience range of conventional jet fuel, with neat o-ring swelling exceeding the typical range of conventional fuels. These results support the potential use of this LJF pathway to complement other SAF pathways and achieve 100% drop-in SAF.

Exergy and Economic Investigation of Different Strategies of Hybrid Systems Consisting of Gas Turbine (GT) and Solid Oxide Fuel Cell (SOFC)

Gas turbines and solid oxide fuel cells can be combined in two different strategies to create a new high-efficiency hybrid system. In most hybrid systems, the fuel cell is located directly before the combustion chamber (pressurized type) or after the turbine (atmospheric type). The indirect hybrid system is another compound that has been less studied. In this system, the fuel cell and the gas turbine cycle are located in two separate cycles and heat exchange was done by a heat exchanger. The main purpose of this article is to compare the exergy and economic performance of direct and indirect hybrid systems. The results show that the direct hybrid system with pressurized fuel cell has better performance than the other two types of hybrid system. High electrical efficiency, low rate of irreversibility and pollution, and low cost of electricity generation, as well as appropriate cost of purchase, installation and system setup, are the characteristics of this type of hybrid systems. Analyzes of this study showed that the only positive feature of direct atmospheric fuel cell systems is high production capacity and indirect hybrid systems are less efficient than direct systems.

Evaluation of a glycolipopepetide biosurfactant from Aeromonas hydrophila RP1 for bioremediation and enhanced oil recovery

Rapid industrialization and anthropogenic activities have significantly contributed to increased petroleum hydrocarbon demand and pollution. For enhancing the oil extraction and removal of organic pollutants from the contaminated soil and water, several physical, chemical, and biological methods have been employed. Among these, bioremediation, and Microbial Enhanced Oil Recovery (MEOR) involving microbes and their metabolites are low-cost and environment-friendly techniques. The present study focused on isolation and identification of bacteria; extraction, purification, and characterization of the biosurfactant; and assessment of the applicability of produced biosurfactant for bioremediation and enhanced oil recovery (EOR). A novel bacterial strain Aeromonas hydrophila RP1 that produces biosurfactant was identified and isolated for the utilization in hydrocarbon degradation and EOR. Characterization by Thin Layer Chromatography, Gas Chromatography-Mass Spectroscopy, Fourier Transform Infrared, and 1H- Nuclear Magnetic Resonance spectroscopy revealed biosurfactant to be of glycolipopeptide nature. Biosurfactant decreased surface tension of water from 72 to 27.4 mN m−1. With a critical micelle concentration of 123 mg L−1, it displayed stability over 4–100 °C temperature, pH of 2–10, and 5–150 g L−1 salinity (as NaCl). Biosurfactant emulsified a range of hydrocarbons like Aviation Turbine Fuel, n-hexadecane, hexane, paraffin oil, and xylene with E24 > 50%. A. hydrophila RP1 displayed moderate affinity (45.77 ± 1.89%) towards hydrocarbons. Biosurfactant facilitated additional ∼28% recovery of the oil and degraded diesel by 77.33% and n-hexadecane by 55.98% after 7 days of incubation. The study demonstrates that glycolipopeptide biosurfactant produced by A. hydrophila RP1 has immense potential for applications in bioremediation and EOR.

Characterization of Water Droplets Size Distribution in Aviation Turbine Fuel: Ultrasonic Homogeniser vs. High Shear Speed Mixer

Characterization of Water Droplets Size Distribution in Aviation Turbine Fuel: Ultrasonic Homogeniser vs. High Shear Speed Mixer

Qualification of Alternative Jet Fuels

Historically, the commercial aviation industry has relied on a very limited number of well-proven, conventional fuels for certification and operation of aircraft and engines. The vast majority of today’s engines and aircraft were designed and certified to operate on one of two basic fuels; kerosene-based fuel for turbine powered aircraft and leaded AVGAS for spark ignition reciprocating engine powered aircraft. These fuels are produced and handled as bulk commodities with multiple producers sending fuel through the distribution system to airports and aircraft. They are defined and controlled by industry consensus-based fuel specifications that, along with the oversight of the ASTM International aviation fuel industry committee, accommodate the need to move the fuel as a commodity. It was therefore expedient to build upon this framework when introducing drop-in jet fuel produced from non-petroleum feed stocks into the supply chain. The process developed by the aviation fuel community utilizes the ASTM International Aviation Fuel Subcommittee (Subcommittee J) to coordinate the evaluation of data and the establishment of specification criteria for new non-petroleum (alternative) drop-in jet fuels. Subcommittee J has issued two standards to facilitate this process; ASTM D4054—“Standard Practice for Qualification and Approval of New Aviation Turbine Fuels and Fuel Additives”, and ASTM D7566—“Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons”. This paper will describe how the aviation fuel community utilizes the ASTM International consensus-based process to evaluate new candidate non-petroleum jet fuels to determine if these new fuels are essentially identical to petroleum derived jet fuel, and, if they are, to issue specifications to control the quality and performance of these fuels.

Aviation Turbine Fuel Thermal Conductivity: A Predictive Approach Using Entropy Scaling-Guided Machine Learning with Experimental Validation.

Although typical aircraft fuel thermal management analysis relies upon temperature-dependent thermodynamic and transport properties of aviation turbine fuel, the variation in properties associated with compositional variation in fuels and the subsequent impacts on system performance are not well established. With this in mind, the present work aimed to develop a predictive model of aviation turbine fuel thermal conductivity which utilized only compositional (hydrocarbon) and state (temperature and pressure) inputs and had errors within the bounds of typical uncertainty of the associated test data (3%). A novel modeling approach was developed to predict thermal conductivity using pseudo-component entropy scaling techniques with a machine learning-developed intermediate step in the overall model. Simple hyper-parameter optimization techniques were developed to promote model stability, computational efficiency, and long-term repeatability of the novel architecture. Validation data were gathered which included four fuel samples (3 JP-5 and 1 F-24), which underwent two-dimensional gas chromatography compositional testing and temperature-dependent density, viscosity, thermal conductivity, and specific heat testing. Model performance on the validation data set assembled from the literature data and present efforts showed an average deviation of 1% and an absolute average deviation of 2.5%. Model outputs outside the validation range are well-behaved and are expected to perform well on a large range of liquid hydrocarbon mixtures with the overall process expected to be well suited to prediction of other properties.

Experimental assessment of the impact of variation in jet fuel properties on spray flame liftoff height

Ensuring efficient and clean combustion performance of liquid-fueled engines requires comprehension of the influence of fuel composition and properties on flame behavior, such as flame liftoff height (LOH) and lean blowout limit (LBO). Spray flame stability is strongly affected by both the fuel reactivity and physical properties. Herein, the flame stability mechanism represented by LOH is investigated for seven jet turbine fuels, including surrogate, alternative, and conventional jet fuels, using a laboratory spray burner. Based on the experimental observations, the current work introduces a new analysis, which provides insight into the competing/complementing processes that occur in a multi-phase reacting system and highlights the key properties important in spray flame dynamics, accounting for both the fuel spray/vaporization as well as the chemical reactivity, to explain the relative differences in LOH of complex multicomponent fuels. Results show that spray flame stabilization occurs when there is a balance between the local spray burning velocity and the incoming jet velocity, which is strongly associated with laminar flame speed and the relative amount of liquid and gaseous fuel crossing the flame preheat region. Using a multicomponent droplet evaporation model, it was observed that preferential vaporization of the lighter and more reactive species of the simple surrogate fuels contribute to a shorter lifted flame as compared to fuels consisting of heavier and/or less reactive components. The LOH of real jet fuels showed strong sensitivity to droplet vaporization and mixing, which is controlled by the fuels’ volatility (i.e., boiling temperature at 50% distillation volume) and atomized droplet size, and to a lesser extent the reactivity represented by laminar flame speed. The enhanced linearity in the correlation of 50% vapor distilled compared to the other distillation cuts suggests that preferential vaporization could play an important role in defining the LOH stabilization mechanism even for more complex fuels.

EXAMINING EVAPORATION CHARACTERISTICS OF TYPICAL AVIATION FUELS INCLUDING JP-4, JP-5, JP-7, RT, Jet A-1 AND TS-1

This work numerically studies the evaporation characteristics of 6 typical gas turbine fuels (JP-4, JP-5, JP-7, RT, Jet A-1, and TS-1, respectively). In this work, the influence of ambient temperature and liquid properties on the droplet lifetime is examined. At the same initial conditions (e.g. fuel temperature Ts0 = 300 K, droplet diameter D0 = 1 mm and atmospheric pressure p = 101.33 kPa) and low ambient temperature (e.g. 500 K), significant differences in evaporation characteristics among these fuels are observed. JP-4 has the longest droplet lifetime while JP-7’s is the shortest. However, at high ambient temperature (e.g. 2000 K), the droplet lifetimes of the fuels are almost identical. Under critical temperature, it is shown that the fuel properties remarkably impact the evaporation rate.

A Degradation Diagnosis Method for Gas Turbine—Fuel Cell Hybrid Systems Using Bayesian Networks

Abstract This paper aims to develop and test Bayesian belief network-based diagnosis methods, which can be used to predict the most likely degradation levels of turbine, compressor, and fuel cell (FC) in a hybrid system based on different sensors measurements. The capability of the diagnosis systems to understand if an abnormal measurement is caused by a component degradation or by a sensor fault is also investigated. The data used both to train and to test the networks are generated from a deterministic model and later modified to consider noise or bias in the sensors. The application of Bayesian belief networks (BBNs) to fuel cell—gas turbine hybrid systems is novel, thus the results obtained from this analysis could be a significant starting point to understand their potential. The diagnosis systems developed for this work provide essential information regarding levels of degradation and presence of faults in a gas turbine, fuel cell and sensors in a fuel cell—gas turbine hybrid system. The Bayesian belief networks proved to have a good level of accuracy for all the scenarios considered, regarding both steady-state and transient operations. This analysis also suggests that in the future a Bayesian belief network could be integrated with the control system to achieve safer and more efficient operations of these plants.

Hydrogenated Turpentine: A Biobased Component for Jet Fuel

The need to find sustainable alternatives to fossil fuels in aviation without requiring drastic structural changes in turbines and tanks has prompted a search for new components to blend with the standard Jet A1. Turpentine obtained by vacuum distillation of resin extracted from the common pine Pinus pinaster or as a byproduct of the paper industry is compared with hydrogenated turpentine at different levels of conversion as a component of jet blends. Properties such as density, kinematic viscosity, heating values, lubricity, flash point, pour point, crystallization onset temperature, and smoke point are reported. Turpentine shows high soot formation tendency. Hydrogenation was carried out as a method to saturate the double bonds of pinenes and to overcome this problem. The performance of four hydrogenated turpentines at different levels of turpentine–hydroturpentine conversion proves improvements in some key properties and especially reductions in the sooting tendency, concluding that partially hydrogenated turpentine can be blended up to 50% v/v with Jet A1, fulfilling the limit required by the standard specification for aviation turbine fuels containing synthesized hydrocarbons.