Jet Fuel Research Articles

Systematic construction of combustion reaction model for large hydrocarbon fuels based on a two-step reaction scheme

Understanding the combustion chemistry of large hydrocarbons in practical gasoline, diesel and jet fuels is critical for the reduction of pollutant emissions and increase of fuel and engine efficiencies. The primary objective of the present study is to illustrate the methodology and application of a simplified modeling approach based on a two-step reaction scheme (TSRS) for describing the combustion chemistry of large hydrocarbon fuels under engine-relevant high-temperature conditions. Under such conditions, the combustion process of large hydrocarbons consists of two distinct subsequent reaction steps: the first step is the prompt fuel decomposition, converting the parent fuel to critical intermediate products; the second step is the oxidation reactions of the intermediates. Particularly, the second step is slower, thus rate-limiting, controlling the heat release and formation of final combustion products of the entire combustion reaction process. A systematic analysis by mathematical methods was performed to obtain a unified treatment for hydrocarbons with different molecular sizes. Based on the analysis of characteristic time scale of elementary reaction and steady-state assumption, TSRS used a fuel decomposition submodel to describe the fuel molecule decompose into critical intermediate species, including ethene, propene, butenes and methane for n-alkanes, and used a detailed foundational fuel chemistry mechanism to describe the oxidation reaction of the intermediates. The entire TSRS reaction model for large hydrocarbons is compact, consisting ∼110 species and ∼800 reactions, which can be further reduced. It was shown in the present study that, by revealing the relationship between the functional group composition of linear alkanes and the distribution of intermediates, and in combination with the rate criterion, the fuel decomposition submodel can be systematically generated to facilitate the automatic construction of compact kinetic models. One unified TSRS combustion reaction model was created and demonstrated for several large hydrocarbons ranging from C8 to C16, which was validated by comprehensive datasets, including speciation, ignition delay times and laminar flame speeds.

Limitations to sustainable renewable jet fuels production attributed to cost than energy-water-food resource availability

Renewable jet fuel (RJF) is often touted as the only viable sustainable energy source for the aviation sector, given the difficulties faced by other low-carbon energy sources in overcoming technological barriers. Despite that, the sustainability of RJF is still in dispute due to the conflicting requirements in natural resource for producing the fuels. We introduce a holistic 25-indicator sustainability index encompassing the four domains of energy-water-food nexus and governance, that measures the potential impact of RJF production on 154 countries (and territories) through the oil-to-jet, alcohol-to-jet and gas-to-jet conversion methods. Countries and territories are ranked according to the composite index scores of the four domains. The sustainability index model provides insights on how RJF affords the aviation sector a clean slate in determining the manner of development in a sustainably and equitable way, while also marching towards the long-term goal of carbon neutrality, in alignment with the Sustainable Development Goals.

Hybrid-electric power unit for an ultralight aircraft

High power-weight ratio, reliability and efficiency are the main design goals for the propulsion system of ultralight aircraft (mass up to 650 kg). For power outputs beyond 40 kW, 4-stroke multi-cylinder SI engines are the most widespread solution, while pure electric powertrains do not appear at the moment as a practical proposition. Four stroke diesel engines would also be very attractive, in particular for military applications, but their weight is significantly higher than their gasoline powered counterpart. The goal of the study presented in this article is to develop a hybrid-electric power unit for ultralights, running on heavy fuels (diesel, kerosene, jet fuels). Reference is made to Falco EVO, by Leonardo, originally equipped by the Rotax 912 ULS/S engine (peak power 73.5 kW, weight about 60 kg): the proposed power unit has the same cylinders layout, smaller overall dimensions and almost equivalent weight. The thermal engine is an innovative two-stroke unit, coupled in parallel to a permanent magnet electric motor. The design and optimization of the hybrid power unit has been supported by CAE tools, including CAD and CFD simulations.The results of the study show that the new hybrid system can save about 30% of fuel mass at the typical cruise conditions, and it can increase the peak power output up to 20%, compared to the reference Rotax engine. The reduction of fuel consumption can be translated into an equivalent increment of the operative range of the aircraft, or into an increase of payload (+30%, considering the Falco EVO aircraft). Finally, compared to the Rotax engine, the hybrid power unit exhibits significantly lower CO2 emissions (from -12% to -37%), thanks to the improvement of fuel efficiency.

Qualitative characterization of oxygen-containing compounds in fuel extracts by using (-) electrospray ionization coupled to a linear quadrupole ion trap/orbitrap mass spectrometer

Qualitative characterization of oxygen-containing compounds (OCCs) in fuels is imperative, as these compounds detrimentally influence fuel stability. Hence, development of analytical methods that enable thorough qualitative information will likely enhance correlations between composition and fuel failures. In this work, (-) electrospray ionization (ESI)coupled to a linear quadrupole ion trap/orbitrap mass spectrometer provided detailed qualitative analysis of OCCs in jet fuels, marine gas oil (MGO)and diesel. The high resolving power and mass accuracy of the orbitrap and soft ionization of ESI advanced the current OCC qualitative knowledge of fuels as the number of OCCs classes identified exceeded previous works. Up to nine, twenty and nine different homologue ion series (i.e.,ions with the same empirical formula (e.g.,CnH2n-7O) but differ by 14 Da (m/z 149, 163, 177, etc.)) were detected in the jet fuels, diesel and MGO, respectively. Additional detailed qualitative information included the average ring and double equivalent values, carbon numbers and molecular weights for the detected OCCs in each fuel. With limited fragmentation of ions, Kendrick Mass Defectplots were made that enabled straightforward comparison of the OCC compositions offuels. Clear qualitative differences were noted among the different types of fuels (i.e.,jet fuels compared to diesel) and when the threejet fuels were compared to each other. As the method demonstrated proficiency at providing detailed compositional information, it may be employed for future storage and thermal stress testing of fuels to monitor and evaluate compositional changes. Overall, the method demonstrated qualitative proficiency and may be used to establish important links between composition and fuel stability; this is a critical prerequisite for improving fuel quality.

Comparative Analysis of Jet Fuel Surrogates Based on a Comprehensive Kinetic Scheme

Comparative Analysis of Jet Fuel Surrogates Based on a Comprehensive Kinetic Scheme

Toward a Real-Fluid Modeling Framework for Sustainable Aviation Fuels

A multi-agency effort is underway to decarbonize the aviation industry by 2050 and replace current fossil fuels such as Jet A. Carbon-free hydrogen-based technologies are a long-term opportunity for some markets, but the introduction of new sustainable aviation fuels (SAF) is necessary for a fleet-wide transition. These biofuels are synthesized to meet specific aviation fuel requirements; thus, they may be used in current jet engines without major modifications (i.e., drop-in SAF), accelerating the transition to net-zero carbon emissions by focusing on the life cycle of the biofuel (i.e., circular economy). Given the increased costs associated with the SAF certification process, a deeper understanding of the biofuel behavior at relevant operating conditions, ranging from take-off to high-altitude relight, becomes necessary to define the best candidates. This work investigates the performance of a real-fluid model (RFM), built upon cubic equations of state, in predicting the relevant fuel properties that dictate the atomization, evaporation, and combustion processes. The simpler composition spectrum of SAFs compared to current fuels justifies the development of this modeling approach targeting its application to computational fluid dynamics (CFD) solvers as a more detailed alternative to typical surrogate mixing rules and tabulated properties. The study showcases the capabilities of the RFM using National Jet Fuels Combustion Program's (NJFCP) Category C fuels and offers guidelines toward the development of reliable and robust fluid-dynamics models to support the adoption of SAF in a broad range of conditions, including transcritical regimes. Here, the behavior of the mixtures challenges the validity of ideal fluid models and, therefore, the proposed formulation allows for a realistic fuel characterization at high-pressure and high-temperature conditions, and to explore beyond the currently available experimental datasets.

Direct Synthesis of a Jet Fuel Range Dicycloalkane from Polycarbonate Waste at a High Concentration

Direct Synthesis of a Jet Fuel Range Dicycloalkane from Polycarbonate Waste at a High Concentration

Method for generating kinetically relevant fuel surrogates based on chemical functional group compositions

Fuel surrogates, simplified representations of complex fuels, play a crucial role in understanding fuel behavior and developing efficient combustion technologies. Previously published surrogates, specifically those designed to model shock tube speciation data, exhibit chemical functional group fragmentation similar in both type and quantity to their parent fuels, suggesting the importance of matching chemical functional groups for surrogates. This paper presents a data-driven optimization procedure for formulating fuel surrogates exclusively by matching chemical functional groups to their parent fuels. The resulting surrogates enable accurate modeling of speciation results, provide valuable insights into reaction kinetics, and are shown to consistently reproduce the ignition quality of their parent fuels, as represented by the Derived Cetane Number (DCN). The method automatically selects the appropriate number and type of components and optimizes their compositions to achieve similar chemical functional group compositions as the target fuel. The applicability of the method is demonstrated by formulating surrogates for two reference jet fuels (Jet-A POSF-10325, F-24), one synthetic alcohol-to-jet fuel (ATJ POSF11498), and a blend of ATJ/F-24 (50/50 vol ratio). Additionally, comparisons of rate of production, rate of progress, and sensitivity analyses in chemical kinetics modeling of the fuels and their surrogates highlight the consistency in outputs between surrogates with different compositions but similar chemical functional group fragmentation.

Validation of a Generic Non-Swirled Multi-Fuel Burner for the Measurement of Flame Stability Limits for Research of Advanced Sustainable Aviation Fuels

Future aviation concepts should be both CO2-neutral and without other emissions. One approach to reaching both targets is based on sustainably produced synthetic liquid fuels, which may allow very clean, lean premixed prevaporized (LPP) combustion. For that, fuels are needed with much longer ignition delay times and a lower flashback propensity than current jet fuels. We describe an experimental setup to investigate the flashback stability of liquid fuels in a multi-fuel burner. In this work, the measurement procedure and the determination of the experimentally obtained accuracy are in focus with regard to prevaporized and preheated iso-propanol/air flames in an equivalence ratio range of 0.85 to 1.05 involving three preheating levels (573, 673, and 773 K). As the determination of the accurate unburnt gas temperature just ahead of the flame is of strong importance for flashback but not directly possible, a model is implemented to determine it from the measurable quantities. Even with this indirect method, and also regarding the hysteresis of the experimental preheating temperature, it is found that the relevant quantities, namely, measured temperatures, mass flows, and values derived from them, can be determined with accuracy in the range below 1.7%.

Effects of hydrogen on PAH and soot formation in laminar diffusion flames of RP-3 jet kerosene and its surrogate

PAH and soot are harmful substances that can be produced in any type of combustion equipment including aircraft engines. The co-combustion of hydrogen and jet fuel has been applied in aero-engine combustors and large-scale hydrogen addition is a promising solution for reducing the consumption of fossil fuels in the aviation industry. However, it remains unclear how H2 influences the soot and PAH formation characteristics of jet kerosene. In this study, to investigate the impact of H2 on soot and PAH formation, planar laser-induced incandescence (PLII), planar laser-induced fluorescence of PAH (PAH-PLIF) and chemical kinetic simulation were conducted for the laminar diffusion flames of RP-3 jet kerosene and its surrogate S1 with different H2 doping rates. It is found that the introduction of H2 leads to the increased soot formation. However, the promotion effect of H2 on the PAH formation weakens as the number of PAH rings increases, and the formation of A4 is significantly inhibited. But the rapidly increase of benzene and alkynes in the H2-doped kerosene flame may ultimately lead to the promotion of soot formation. Furthermore, the changes in direct synthesis reactions and PAH=>PAH- jointly affect the converse changes in A1 and A4 formation. These findings will contribute to the development of the soot model and soot/PAH-reduction strategy for the co-combustion of jet fuels and hydrogen.

Development of a diesel surrogate for improved autoignition prediction: Methodology and detailed chemical kinetic modeling

While the surrogate fuel approach has been successfully applied to the simulation of the combustion behaviors of complex gasoline and jet fuels, its application to diesel fuels has been challenging. One of the main challenges derives from the large molecular size of the representative surrogate components necessary to simulate diesel blends, as the development of detailed chemical kinetic models and their validation becomes more complex. In this study, a new surrogate mixture that emulates the chemical and physical properties of a well-characterized diesel fuel is proposed. An optimization procedure was used to select surrogate components that can match both the physical and chemical properties of the target diesel fuel comprehensively. The surrogate fuel mixture composition was designed to have fuel properties (e.g., boiling point, cloud point, etc.) that enable its use in future diesel engine experiments. A detailed kinetic model for the surrogate fuel mixture was developed by combining well-validated sub-mechanisms of each surrogate component from Lawrence Livermore National Laboratory. The ability of the surrogate mixture and kinetic model to emulate ignition delay times was assessed by comparing the simulated results with measurements for the target diesel fuel. Comparison of the experimental and simulated ignition delay times shows that the current surrogate mixture and kinetic model well capture the autoignition response of the target diesel fuel at varying conditions of pressure, temperature, oxygen concentration, and fuel concentration. The current study is one of the first to demonstrate the efficacy of detailed chemical kinetics for diesel range fuels by assembling validated sub-mechanisms for palette compounds and successfully simulating the autoignition characteristics of a target diesel fuel. The experimental ignition delay times of diesel measured with a rapid compression machine, the surrogate mixture, and the kinetic model developed shall aid in progress of understanding diesel ignition under engine relevant conditions.

Counterintuitive Catalytic Reactivity of the Aluminum Oxide "Passivation" Shell of Aluminum Nanoparticles Facilitating the Thermal Decomposition of exo-Tetrahydrodicyclopentadiene (JP-10).

High energy density aluminum nanoparticles (AlNPs) have been at the center of attention as additives to hydrocarbon jet fuels like exo-tetrahydrodicyclopentadiene (JP-10, C10H16) aiming at the superior performance of volume-limited air-breathing propulsion systems. However, a fundamental understanding of the ignition and combustion chemistry of JP-10 in the presence of AlNPs has been elusive. Exploiting an isomer-selective comprehensive identification of the decomposition products in a newly designed high-temperature chemical microreactor coupled to vacuum ultraviolet photoionization, we reveal an active low-temperature heterogeneous surface chemistry commencing at 650 K involving the alumina (Al2O3) shell. Contrary to textbook knowledge of an "inactive alumina surface", this unconventional reactivity, where oxygen is transferred from alumina to JP-10, leads to generating cyclic, oxygenated organics like phenol (C6H5OH) and 2,4-cyclopentadiene-1-one (C5H4O)─key tracers of an alumina-mediated interfacial chemistry. This counterintuitive reactivity transforms our knowledge of the (catalytic) processes of alumina-coated AlNPs on the molecular level.

Blow-off of fuel jet flames in the atmosphere

Further data from experiments with the atmospheric burning of jet fuels, particularly their blow-off and flame quenching characteristics, have been collected and interpreted. These are characterised in terms of both their dimensionless Flow Number and Flame Thickness. Regimes of Lifted Flames, Flame Blow-off, Choked Flow and Flame Quench have been defined by these Dimensionless Groups. New data are presented for a variety of hydrocarbon and ammonia-hydrogen fuels. New techniques are required for the assessment of the latter, including derivation of their acoustic velocities and the characterisation of their laminar flames, including burning velocity and flame thickness. It is possible to create NH3+H2 jet flow blends with burning rates and blow-off velocities that are closer to those of hydrocarbons than of H2. The properties of individual fuels are displayed in terms of the fuel velocities at which blow-off occurs for different pipe diameters. The properties of individual fuels displayed in this way show a greater diversity than is evident from the dimensionless groups. Similarities are drawn between premixed and jet flow flame quenching.

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.

Development of Physical-Chemical Surrogate Models and Skeletal Mechanisms for the Combustion Simulation of Several Jet Fuels

Abstract The physical–chemical surrogate models for S-8, Jet-A, and RP-3 fuels to capture their physical and kinetics properties have been developed in this study. n-dodecane (nC12H26), 2,5-dimethylhexane (C8H18-25), and toluene (C6H5CH3) were chosen as candidate surrogate components and formulated by the function group based surrogate fuel methodology. Some important physical properties and spray characteristics for S-8, Jet-A, and RP-3 surrogate models were validated. The results indicate that present surrogate models can well emulate various physical properties to accurately reproduce the spray characteristics. Then, a minimal and high-precision surrogate skeletal mechanism that can be suitable for computational fluid dynamics (CFD) simulations was developed and validated against some fundamental combustion experiments for each surrogate component. Furthermore, the performances of surrogate models that contain the surrogate formulation and associated skeletal mechanisms were validated against the experimental data on ignition delay times (IDTs), species concentration profiles, and laminar flame speeds (Su0) in a wide range of conditions. Finally, the surrogate fuels were used to combustion CFD simulations to model the spray combustion process in a constant volume combustion chamber. It can be seen that the agreements between the simulation and experiment in fundamental and spray combustion characteristics are reasonably good, which proves that present surrogate models are accurate and robust to be applied in CFD simulations.

Application of Mesoporous NiMo/Silica (NiMo/SiO2) as a Catalyst in the Hydrocracking of Used Cooking Oil into Jet Fuel

Application of Mesoporous NiMo/Silica (NiMo/SiO2) as a Catalyst in the Hydrocracking of Used Cooking Oil into Jet Fuel

Formulation of a Jet Fuel Surrogate and Its Kinetic Chemical Mechanism by Emulating Physical and Chemical Properties of Real Jet Fuel

The application of jet fuel in gas turbines and diesel engines adheres to the Army’s single-fuel forward policy, streamlining supply chains. To ensure precise engine combustion numerical studies, surrogate fuels and mechanisms should faithfully replicate real fuel properties and combustion traits. In this work, a new four-component jet fuel surrogate containing 39.05% n-dodecane/21.79% isocetane/11.49% decalin/27.67% toluene by mole fraction is formulated based on a property optimizer. The new-formulated fuel surrogate can satisfactorily emulate the chemical and physical properties of real jet fuel, including cetane number (CN), threshold sooting index (TSI), molecular weight (MW), lower heating value (LHV), the ratio of hydrogen and carbon (H/C), liquid density, viscosity, and surface tension. Furthermore, a reduced and robust kinetic chemical mechanism (containing 124 species and 590 reactions) that could be directly employed in practical engine combustion simulations has also been developed for the proposed surrogate jet fuel. The mechanism is validated through comprehensive experimental data, including ignition delay time (IDT) determined in shock tubes and rapid compression machines (RCMs), species mole fractions measured in premixed flames and jet stirred reactors (JSRs), and laminar flame speeds. Generally, the property deviations of the jet fuel surrogate are less than 2% except for MW (10.73%), viscosity (5.88%), and surface tension (8.71%). The comparison results between the predictions and measurements are in good agreement, indicating that the current kinetic mechanism is capable of reflecting the oxidation process of real jet fuel. The current mechanism can accurately capture variations in the ignition delay time in the negative temperature coefficient (NTC) region as well. In the future, the proposed surrogate jet fuel could be applied in practical engine computational fluid dynamic (CFD) simulations.

Jet Fuel Price Risk and Proxy Hedging in Spot Markets: A Two-Tier Model Analysis

This paper applies a two-tier model based on fuel hedging (model 1) and the testing of the impact of commodity risk on airline capacity forecasting, which is based on a system dynamics framework (model 2). Model 1 provides a comprehensive examination of the worldwide airline industry, including an analysis of the statistical impact of oil price fluctuations on the sector and the corresponding hedging strategies employed by airlines. This study examines a sample of North American and European airlines over a 10-year timeframe to assess the degree to which these airlines have engaged in kerosene hedging for future periods and the potential impact of such hedging on their corporate value and performance. In model 2, the author integrates a capacity-forecasting model within the system dynamics framework, drawing upon the theory of capacity forecasting. The study examines the impact of commodity risk by analysing the influence of fluctuations in the jet fuel spot price on the average airfare and its subsequent effects on other interdependent capacity variables. The hypotheses presented in this study were formulated based on a comprehensive review of the relevant literature and a causal feedback loop diagram. The diagram effectively depicts the dynamic interrelationships between capacity forecasting and risk variables. Furthermore, the diagram capturing causal feedback loops was transformed into a stock-flow diagram. This diagram was then utilised to evaluate the hypotheses that were derived using a dataset that pertains to the domestic airline market in the United States. The verification of the qualitative and quantitative models demonstrates the proven impact of commodity risk on capacity forecasting.

Enabling cuboid-based fisher ratio analysis using total-transfer comprehensive three-dimensional gas chromatography with time-of-flight mass spectrometry

Comprehensive three-dimensional (3D) gas chromatography with time-of-flight mass spectrometry (GC3-TOFMS) is a promising instrumental platform for the separation of volatiles and semi-volatiles due to its increased peak capacity and selectivity relative to comprehensive two-dimensional gas chromatography with TOFMS (GC×GC-TOFMS). Given the recent advances in GC3-TOFMS instrumentation, new data analysis methods are now required to analyze its complex data structure efficiently and effectively. This report highlights the development of a cuboid-based Fisher ratio (F-ratio) analysis for supervised, non-targeted studies. This approach builds upon the previously reported tile-based F-ratio software for GC×GC-TOFMS data. Cuboid-based F-ratio analysis is enabled by constructing 3D cuboids within the GC3-TOFMS chromatogram and calculating F-ratios for every cuboid on a per-mass channel basis. This methodology is evaluated using a GC3-TOFMS data set of jet fuel spiked with both non-native and native components. The neat and spiked jet fuels were collected on a total-transfer (100 % duty cycle) GC3-TOFMS instrument, employing thermal modulation between the first (1D) and second dimension (2D) columns and dynamic pressure gradient modulation between the 2D and third dimension (3D) columns. In total, cuboid-based F-ratio analysis discovered 32 spiked analytes in the top 50 hits at concentration ratios as low as 1.1. In contrast, tile-based F-ratio analysis of the corresponding GC×GC-TOFMS data only discovered 28 of the spiked analytes total, with only 25 of them in the top 50 hits. Along with discovering more analytes, cuboid-based F-ratio analysis of GC3-TOFMS data resulted in fewer false positives. The increased discoverability is due to the added peak capacity and selectivity provided by the 3D column with GC3-TOFMS resulting in improved chromatographic resolution.

Experimental study of droplet vaporization for conventional and renewable transportation fuels: Effects of physical properties and chemical composition

As part of the global energy transition, an increasing number of sustainable liquid fuels with a wide range of physical and chemical properties becomes available for gas turbine and IC engines. For an optimal design and operation of these engines, an improved understanding of the effects of fuel properties on atomization, vaporization and combustion kinetics is required. The present work provides a comprehensive experimental study of fuel effects on droplet vaporization for numerous conventional and alternative fuels. The study employs a recently developed flow channel, where free-falling droplets with initial diameters of D≈77μm vaporize under technically relevant gas temperatures Tg of up to 1300 K. The evolution of droplet diameters over travel distance and time is measured using microscopic shadow imaging. A total of 13 single fuel components, five bi- and tri-component mixtures, six conventional and alternative jet fuels and mixtures thereof, and three IC engine fuels and mixtures thereof have been tested under well-reproducible ambient conditions. The fuels represent a wide range of chemical classes such as n-alkanes, iso-alkanes, cycloalkanes, aromatics, alcohols and oxymethylene ethers, and most of them were measured for the first time with realistic D and Tg. The results for the single fuel components reveal in detail the temperature-dependent effects of physical properties such as boiling point Tb, liquid density ρl and enthalpy of vaporization Hv. In particular, it was found that for high gas temperatures of about 1250 K, the vaporization rate is almost completely determined by the product of Hv and ρl. By comparison with the results for single n-alkanes, the measurements for bi- and tri-component mixtures accurately characterize the preferential vaporization of individual fuel components over droplet lifetime. The results for various multi-component fuels reveal complex interplays of preferential vaporization and temperature-dependent influences of physical properties. It is shown that the vaporization for conventional and corresponding alternative fuels can differ significantly. Finally, the droplet vaporization is characterized for mixtures of PRF90+ethanol and ethanol+water, which exhibit a non-ideal vapor–liquid equilibrium.