Surrogate Fuels Research Articles

Optimization method for the component of aviation kerosene surrogate fuels based on chemical reactor network model

On the basis of the simulation results of premixed jet flame using liquid hydrocarbon fuel, an optimization method for the component of aviation kerosene surrogate fuels based on chemical reactor network (CRN) model is proposed. Firstly, computational fluid dynamics (CFD) numerical simulation is carried out for three hydrocarbon fuel jet flames of n-dodecane (C12H26), n-decane (C10H22), n-heptane (C7H16) to obtain the characteristics of the temperature field under different working conditions. Based on this, the CRN partition topological geometry of jet flame is generated. The genetic algorithm is used to optimize the parameters of each reactor, and the algebraic relationship between the CRN parameter and the inlet parameters (dimensionless inlet temperature, Reynolds number and mixing fraction) is obtained. Then, topological geometry of the CRN which is suitable for different working conditions is established, and the best CRN model of hydrocarbon fuel jet flame is constructed. Combined with the experimental data, the optimal proportion of three-component surrogate fuels is determined by the above method. As a result, the optimal ratio is 56.41% C12H26, 26.36% C10H22 and 17.23% C7H16. Finally, the CFD numerical simulation was performed and the results agreed well with the experimental data, indicating the effectiveness of optimization method for the CRN-based aviation kerosene surrogate fuels. This method can be applied to the component optimization of aviation kerosene surrogate fuels.

Low temperature autoignition of Jet A and surrogate jet fuel

An experimental study of the low-temperature and low-pressure autoignition of Jet A and surrogate fuels was conducted using the ASTM-E659 standardized test method. Two surrogate fuels (Aachen and JI mixtures), their individual components and two batches (POSF-4658 and POSF-10325) of standardized Jet A were tested using the ASTM-E659 method for a range of fuel concentrations and temperatures. The ignition behaviors were categorized into four distinct ignition modes. The individual hydrocarbon components had a wide range of ignition behaviors and minimum autoignition temperatures (AIT) values depending on the molecular structure. The two Jet A batches showed similar ignition behavior with measured AITs of 229 ±3°C and 225 ±3°C respectively. Both surrogates exhibited similar ignition behavior to Jet A with comparable AITs of 219 ±3.1°C (Aachen) and 228 ±3°C (JI) with the JI mixture proving to be a more suitable surrogate to Jet A in the low-temperature thermal ignition regime.

Modeling spray combustion using multi-component surrogate fuels

Kerosene and diesel fuels involved in spray combustion operations are complex fuels composed of a wide and diverse variety of hydrocarbon components. For practical numerical modeling of the evaporation and combustion phenomena in a combustor, well-designed surrogates fuels that can mimic the real fuel thermal and chemical properties can be utilized. In this study, predictions and validations of the influence of fuel on the liquid and vapor penetration characteristics within a constant-volume chamber were first performed utilizing a benchmark m-xylene/ n-dodecane, Jet-A, and diesel surrogate fuels. Then, simulations of reacting spray of a bi-component m-xylene/ n-dodecane fule, and a four-component Jet-A surrogate fuel ( n-dodecane (C12H26), iso-cetane (C16H34), trans-decalin (C10H18) and toluene (C7H8)) were studied aided by skeleton chemical kinetic mechanisms available from the literature. The results of ignition delay time, lift-off length, radicals, and the mass fraction histories of fuel species were comprehensively used to assess the performance of relevant thermophysical and chemical sub-models. Two different chemical mechanisms were compared in detail to investigate the effect of the chemical kinetics model on the flame structures and spray characteristics. It has been found that the spray ignition of multi-component fuels is remarkably influenced by the chosen chemical kinetic mechanism and less affected by the droplet evaporation models.

Liquid–Liquid Phase Behavior of Diesel/Biofuel Blends: Ternary Mixtures of n-Hexadecane, 2,2,4,4,6,8,8-Heptamethylnonane, and Ethanol and the Binary Subsystems

Mixtures of n-hexadecane and 2,2,4,4,6,8,8-heptamethylnonane are common diesel fuel surrogates. This paper describes a systematic investigation of the liquid–liquid phase behavior of the ternary mixtures of the normal alkane n-hexadecane and its isomer 2,2,4,4,6,8,8-heptamethylnonane (both CnH2n+2; n = 16) with ethanol as a model system of surrogate fuels. By applying the cloud point method in the temperature range of T = 240–330 K at ambient pressure (p = 1013 mbar), the complete liquid–liquid phase diagram is obtained. The binary mixtures of the alcohol with both isomeric alkanes show partial miscibility with upper critical solution points. The behavior of the ternary mixtures is examined by investigating the quasi-binary subsystems of mixtures of the alcohol with mixtures of the two isomers for various fixed mole ratios. By changing the ratio of the different isomers, the region of the phase diagram of the alcohol mixture with the n-alkane is gradually shifted toward lower temperatures when adding the branched isomer toward the phase diagram of the binary mixture of the alcohol with the isomeric compound. The general shape of the phase bodies of the pseudobinaries, predefined by the ratio of the isomeric components, shows only a slight change. For the numerical analysis of the measured phase behavior of the pseudobinary mixtures, concepts are used that are applied for binary solutions presuming Ising criticality. A master curve is obtained when applying the corresponding state principle on the binary and the pseudobinary mixtures. Superposition of the different results allows for a comprehensive description of the liquid–liquid phase behavior, and it estimates the loci of critical line and tie lines. The limits of the range of validity of the descriptions are determined by the appearance of solid phases, which are also reported here. This study is expected to establish a basis for optimizing blends of petrochemical fuels and fuels from renewable sources.

Development of a skeletal mechanism for four-component biodiesel surrogate fuel with PAH

A four-component skeletal mechanism consisting of 1,4-hexadiene, methyl decanoate, methyl trans-3-hexenoate, n-hexadecane was developed to represent biodiesel fuel from various sources. The methyl decanoate and n-hexadecane were selected to represent saturated fatty acid methyl esters, and trans-3-hexenoate and 1,4-hexadiene were applied to adjust degree of unsaturation. A skeletal mechanism for this four-component biodiesel surrogate fuel with PAH was first formulated based on decoupling methodology, which contained a detailed C1 mechanism, a reduced C2–C3 mechanism, PAH mechanism and sub-mechanisms of four surrogate fuels, including 314 reactions and 98 species. After that, the skeletal mechanism was widely verified against various fundamental combustion experiments for each pure component and their mixtures. Furthermore, the experimental results of biodiesel soot volume fractions from biodiesel spray combustion in a constant-volume combustion vessel were used to verify the accuracy of the mechanism, and the skeletal mechanism was also coupled into the CFD-software to simulate the combustion characteristics of a diesel engine. Results showed that the calculated results agreed well with the experimental data including ignition delay times (IDTs), primary species concentrations, laminar flame speed, soot prediction and in-cylinder pressure of the engine. Overall, the developed compact skeletal mechanism was suitable for the combustion simulation of biodiesel fuel.

Catalytic combustion of methyl butanoate over HZSM-5 zeolites.

Catalytic combustion technology is an exciting prospect for the removal of pollutants, especially in the field of transportation. Applying zeolites in fuel combustion has gained increasing importance in heterogeneous catalysis arising from their properties such as economical practicability and high activity. However, compared with the extensively investigated homogeneous combustion, few studies have been reported to explore the catalytic combustion of large-molecule fuels, especially for the catalytic combustion of biodiesel surrogate fuels. The purpose of this feature article is to describe the catalytic combustion of methyl butanoate (one of the biodiesel surrogate fuels) over unmodified HZSM-5 zeolites with a particular focus on the catalytic reaction mechanism. Experiments and theoretical calculations were considered here to help explain the proposed catalytic mechanism. This paper can provide new insights into the catalytic mechanism of biodiesel fuels that will guide the improvement of combustion efficiency in internal combustion engines and in the control of pollutant emissions.

Effect of Lagrangian-phase Modelling on Charge Stratification and Spatial Distribution of Threshold Soot Index for Toluene Reference Fuel Surrogates

Nowadays, soot emissions are one of the major concerns in Direct Injection Spark Ignition engines. Soot prediction models can be computationally expensive, especially when particle mass, number, and size distribution are to be forecast. While soot formation heavily depends on the chemical and physical characteristics of the fuel, the simulation of the exact composition of a real gasoline is computationally unfeasible. Thus, it is essential to find simplified yet representative pathways to reduce the computational cost of the simulations. On the one hand, the a-priori investigation of the factors influencing particulate onset can be a simplified approach to compare different solutions and strategies with much cheaper costs than the modelling of soot formation and oxidation mechanisms. On the other hand, the use of surrogate fuels is a practical approach to cope with the fuel chemical nature. Although they poorly mimic the evaporation properties of a real gasoline, Toluene Reference Fuels are broadly adopted to match combustion relevant properties of the real fuels. In this study, the spatial distribution of the Threshold Soot Index in the fluid domain is investigated for three surrogates characterized by an increasing content of toluene (0 mol%, 30 mol%, 60 mol%). The correlation between the sooting tendency and the fuel distribution in the combustion chamber before spark ignition time can provide useful preliminary indications, without spending the computational effort of the whole soot model multicycle resolution. In particular, two approaches for the lagrangian description of the injected fuel are investigated: a multicomponent approach and a single component one, this last driven by a high-fidelity lumped modelling of the surrogate properties for both liquid and vapor phase.

Assessment of the Oxidative Desulfurization of Middle Distillate Surrogate Fuels with Spectroscopic Techniques.

The oxidative desulfurization of five (5) model sulfur compounds and eleven (11) surrogate blends was investigated using the hydrogen peroxide (H2O2)-acetic acid (CH3COOH) system. Consequently, extractive desulfurization was carried out using conventional solvents. The model sulfur compounds, as well as the solvent, are present in petroleum middle distillates. The selection of the compounds was made so that they represent various kinds of sulfur compounds. The goal of this study was the implementation of a simple and economical oxidative and extractive system for the desulfurization of surrogate mixtures with an intermediate sulfur concentration 1% w/w, at the mild temperature of 70°C, and without the use of supplementary and assisting methods such as heterogeneous catalysis or ultrasound irradiation. The sulfur content was estimated using X-ray fluorescence. The progress of the oxidation reaction was monitored using liquid FT-IR. The solid sediments of the oxidation procedure were identified with solid-state FT-IR and 1H NMR spectroscopy.

A merged kinetic mechanism study of two aviation surrogate fuels

A detailed chemical reaction kinetic mechanism involving 1181 species and 6964 reactions was developed for the combustion of two-components (surrogate A) and three-components (surrogate B) surrogate fuels for JP-8 and RP-3. The low temperature oxidation characteristics of the two surrogate fuels were compared regarding the aspects of components difference, negative temperature coefficient (NTC), intermediates and products formation. The surrogate A consists of 77.0% n-decane (NC10H22) and 23.0% 1,3,5-trimethylbenzene (T135MB) by mole fraction. The composition of surrogate B is 66.2% n-dodecane (NC12H26), 15.8% n-propylbenzene (NPB or A1C3H7) and 18.0% 1,3,5-trimethylcyclohexane (T135MCH) by mole fraction. The initial reaction temperature, NTC temperature range and fuel depletion temperature of surrogate A are significantly lower than those of surrogate B. Surrogate A tends to produce more aromatics and oxygenates than surrogate B in terms of quantity and type. Acetaldehyde was observed in the oxidation of the two surrogate fuels, while methanol, ethanol, acrylaldehyde, 1-propanol, 2-propanol and acetone were only detected in surrogate A oxidation. According to ROP analysis, T135MB is consumed mainly by methyl abstraction reactions. However, consumption of NPB is dominated by decompositions on the propyl group. Sensitivity analysis indicates that the reactions H2O2(+M)<=>OH + OH(+M) and HO2 + HO2<=>H2O2 + O2 are the most promoting and inhibiting reactions on T135MB and NPB consumption. Moreover, the present mechanism could reproduce the ignition delay times of JP-8 and RP-3 surrogates. As the merged mechanism could simulate the macro and micro characteristics of fuel and surrogate fuel reasonably, it will be helpful to deepen the understanding of combustion process of aviation fuels.

Combustion of methylcyclohexane at elevated temperatures to investigate burning velocity for surrogate fuel development

To overcome the complexity associated with the development of detailed kinetic models for real transportation fuels, surrogate fuel models offer an excellent alternative. The present study reports laminar burning velocity (LBV) measurements of methylcyclohexane (MCH) + air mixtures for mixture temperatures up to 610 K using externally heated diverging channel method (EHDC) method at 1 atm pressure. MCH is a commonly used surrogate blend for aviation fuels, gasoline, and diesel, whose kinetic model is simpler to develop. The measurement of laminar burning velocity forms the basis of kinetic model development for such surrogate fuels. The present work reports the measured LBV values for an equivalence ratio range, φ = 0.7–1.4, and their comparison with available experimental data and detailed kinetic model predictions for a mixture temperature range, 353–610 K. Temperature exponent, α is derived using the power-law correlation and good consistency with kinetic model predictions is observed up to 500 K mixture temperatures. At 610 K mixture temperature, an overprediction of ≈12% at φ = 1.05 is observed with JeTSurF 2.0 (2010) model and 27% overprediction with the kinetic model of PoliMi (2014) φ = 1.1. Overall, the reported LBV measurements show slightly better match with the JeTSurF 2.0 (2010) kinetic model than the Wang (2014) kinetic model. Reaction pathway diagrams are drawn to highlight the importance of C2H4 and C2H3 radicals for an increase in the overall reaction rate at 610 K.

A detailed chemical kinetic modeling and experimental investigation of the low‐ and high‐temperature chemistry of n‐butylcyclohexane

AbstractChemical kinetic models of gasoline, jet, and diesel fuels and their mixtures with bioderived fuels are needed to assess fuel property effects on efficiency, emissions, and other performance metrics in internal combustion and gas turbine engines. As these real fuels have too many fuel components to be included in a chemical kinetic model, surrogate fuels containing fewer components are used to represent them. These surrogate fuels mimic the chemical classes or molecular structures contained in the real fuel. One of the important chemical classes in gasoline, jet, and diesel fuels comprises cyclohexanes. Cyclohexanes comprise about 30% or more by weight in diesel fuel. Also, Mueller et al (Energy Fuels. 2012;26(6):3284‐3303) proposed n‐butylcyclohexane (nBCH) as a component in a nine‐component surrogate palette to represent the ignition properties, distillation curve, density, and molecular structures of a diesel certification fuel. In this work, experimental measurements of the ignition delay times (IDTs) of nBCH in a shock tube and in a rapid compression machine are reported over a wide range of temperature, pressure, and equivalence ratio important for enabling the validation of a chemical kinetic model for nBCH for combustion in diesel engines. The range of conditions are temperatures of 630–1420 K, pressures of 10, 30, and 50 bar, and equivalence ratios of 0.3, 0.5, 1.0, and 2.0 in ‘air’. A detailed chemical model is developed for nBCH to simulate its ignition at both low and high‐temperature conditions and at relevant elevated pressures. The experimentally measured IDTs are used to improve and validate the chemical kinetic model.

Laminar burning velocity measurements of iso-octane + air mixtures at higher unburnt mixture temperatures

Surrogate fuels offer an effective and efficient alternative in predicting the combustion characteristics of various practical fuels such as gasoline, kerosene and diesel. Once standardized, the chosen constituents of the surrogate fuels help reduce the complexity involved in the development of detailed kinetic models for engine simulations at global scales. In this study, with air being the oxidizer, iso-octane as a surrogate constituent of the gasoline fuel is used for measuring the laminar burning velocities at high mixture temperatures. Present investigations report LBV measurements for a temperature range of 300–640 K using an externally heated diverging channel (EHDC) method. The comparison is then carried out with the available experimental data in the literature and kinetic model predictions at 1 atm pressure for an equivalence ratio range of ϕ = 0.7–1.4. Temperature exponent, (α) is derived using the power-law correlation and a good consistency is observed between the current measurements and the kinetic model predictions of LLNL-V3 (2008) and Hasse (2000) for a temperature ratio of 1.7 and 1.8 respectively. Reaction pathway analysis exhibits that the presence of species TC3H6CHO at 470 K leads to a lower LBV than at 640 K. Methyl radical, CH3 plays a significant role in the auto-ignition phenomena as highlighted from the sensitivity analysis at ϕ = 1.1. The present study also becomes vital in terms of improving the detailed kinetic models targeting the prediction of knocking propensity.

An experimental and kinetic modeling study of cyclopentane and dimethyl ether blends

Cyclopentane is a suitable naphthene, or cycloalkane, in a palette for multi-component gasoline surrogate fuels due to its presence in market fuels and its relevance to alkyl substituted cyclopentanes also present. However, the previous oxidation studies of cyclopentane have primarily focused on neat mixtures. Blending cyclopentane with dimethyl ether in this work therefore serves to inform our understanding of, and improve predictive models for, multi-component mixtures. In this work, the auto-ignition of cyclopentane/dimethyl ether blends was studied in a high-pressure shock tube and in a rapid compression machine. A wide range of temperatures (650 – 1350 K) and elevated pressures of 20 and 40 bar were studied at equivalence ratios of 0.5, 1.0 and 2.0 in air for two blending ratios (30/70 and 70/30 mole% cyclopentane/di-methyl ether mixtures). A detailed kinetic model for cyclopentane was revised to capture the measured ignition delay times and apparent heat release rates in this study. Literature ignition delay time, jet-stirred reactor, and laminar burning velocity measurements of neat cyclopentane were used as additional validation. Improvements to the kinetic model were based on recent literature studies related to sub-models including cyclopentene and cyclopentadiene which allowed the removal of previous local rate-constant optimizations. Low temperature reactivity of cyclopentane was found to be controlled by the branching ratio between concerted elimination of HȮ2 and the strained formation of Q˙OOH radicals in agreement with previous studies. In this study, the low branching ratio of Q˙OOH formation increases the influence of a competing consumption pathway for cyclopentyl-peroxy (CPTȮ2J) radicals. The sensitivity of the simulated ignition delay times to the formation of cyclopentyl hydroperoxide (CPTO2H), from CPTȮ2J and HȮ2, is discussed. The current model is used to analyze the influence of dimethyl ether on the reactivity of cyclopentane in the context of previous literature studies of dimethyl ether binary blends with ethanol and toluene.

Deactivation of Ni-Al-Based Catalysts for Autothermal Reforming of Diesel Surrogate Fuel in the Presence of an Aromatic Hydrocarbon.

Diesel fuel can produce higher concentrations of H₂ and CO gases than other types of hydrocarbon fuels via a reforming reaction for solid oxide fuel cells (SOFCs). However, in addition to sulfur compounds and aromatic hydrocarbons in diesel fuel are a major cause of catalyst deactivation. To elucidate the phenomenon of catalyst deactivation in the presence of an aromatic hydrocarbon, dodecane (C12H26) and hexadecane (C16H34) were blended with an aromatic hydrocarbon such as 1-methylnaphthalene (C11H10) to obtain a diesel surrogate fuel. The experiments were performed for autothermal reforming of the diesel surrogate fuel under conditions of S/C = 1.17, O₂/C = 0.24, 750°C and GHSV= 12,000 h-1. Three Ni-Al-based catalysts with 10 wt% (N10A), 30 wt% (N30A) and 50 wt% (N50A) of NiO were prepared via the polymer modified incipient method. Whereas all of the Ni-Al-based catalysts were deactivated with increasing reaction time, the catalysts with greater Ni contents tended to maintain their catalytic performance for a longer time. Correlation between the catalytic performances and Ni content were analyzed by temperature-programmed reduction (TPR), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope with energy-dispersive X-ray spectroscopy (SEM-EDX), Brunauer-Emmett-Teller(BET) analysis, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Also, we concluded that ethylene (C₂H₄), which was detected by gas chromatography-mass spectrometry (GC-MS), was the fundamental cause of deactivation of the Ni-Al-based catalysts by accelerating the deposition of wire-type carbon on the catalytic surface.

PAH 成長にセクショナル法を適用したガソリンサロゲート燃料用すす生成モデル（第2 報）:－ イソオクタン/トルエン/エタノール混合燃料のすす生成特性 －

PAH 成長にセクショナル法を適用したガソリンサロゲート燃料用すす生成モデル（第2 報）:－ イソオクタン/トルエン/エタノール混合燃料のすす生成特性 －

Sooting Propensity Estimation of Jet Aviation Fuel Surrogates and Their n-Alkane Components by the Virtual Smoke Point Method

Sooting Propensity Estimation of Jet Aviation Fuel Surrogates and Their <i>n</i>-Alkane Components by the Virtual Smoke Point Method

Hybrid low-carbon high-octane oxygenated gasoline based on low-octane hydrocarbon fractions

Low-carbon fuel is the main trend in the development of oil refining in leading countries. Likewise, efforts continue optimizing internal combustion engines for increasing their fuel economy, and therefore exhaust emissions will be reduced. This research proposes a novel approach for producing low-carbon high-octane oxygenated environmentally friendly motor gasoline based on low-octane hydrocarbon fractions. Experimental studies of the antiknock performance for four representatives of oxygenated compounds, involving bioethanol, methyl tertiary butyl ether (MTBE), isopropanol, and 2-methylfuran with low-octane hydrocarbon fractions, as well as low-octane blends of individual hydrocarbons of surrogate fuels were carried out. Additionally, the change in antilocking performance of oxygenated compounds has been dependent on their types and group composition of the base low-octane motor fuel. The results illustrated that high-octane environmentally friendly motor gasolines RON 91 and RON 95 have been produced. Besides, the injectivity of hydrocarbons to oxygenated compounds by the ability to increase the octane rating by the research method will increase in the series: olefins < naphthenes < aromatics < paraffins, and by the motor method:naphthenes < olefins < aromatics < paraffins. Finally, environmentally friendly motor gasoline can decrease the environment impacts, reduce the overhead charges, as well as maximize the product quality.

THIP: A new TPRF-like fuel surrogate development approach to better match real fuel properties

Simple surrogate formulations for gasoline are useful for modelling purposes and for comparing experimental results using a carefully designed fuel. Simple three component surrogate fuels based on toluene, n-heptane and isooctane, called toluene primary reference fuels (TPRF), are frequently used to match the RON and MON of actual gasoline fuels.In this work the main advantages of using an alternative three-component surrogate formulation, based on toluene, n-heptane and isopentane (THIP) are presented. Given a reference gasoline, good representations of RON and MON are achieved as well as better matching density, distillation properties and other volatility parameters associated with the lighter end of gasoline fuels. In particular, THIP surrogates can replicate Dry Vapour Pressure Equivalent (DVPE) values ranging from 10.4 kPa to 138.9 kPa, fully covering the EN228 Summer and Winter gasoline specifications. Moreover, Rapid Compression Machine (RCM) results demonstrate that THIP surrogates can reproduce the essential characteristics of the reference gasoline in terms of ignition delay time versus temperature. An existing chemical kinetic mechanism is shown to be able represent THIP surrogate well.

A comprehensive experimental and kinetic modeling study of 1- and 2-pentene

Abstract 1- and 2-pentene are components in gasoline and are also used as representative alkene components in gasoline surrogate fuels. Most of the available ignition delay time data in the literature for these fuels are limited to low pressures, high temperatures and highly diluted conditions, which limits the kinetic model development and validation potential of these fuels. Therefore, ignition delay time measurements under engine-like conditions are needed to provide target data to understand their low-temperature fuel chemistry and extend their chemical kinetic validation to lower temperatures and higher pressures. In this study, both a high-pressure shock tube and a rapid compression machine have been employed to measure ignition delay times of 1- and 2-pentene over a wide temperature range (600–1300 K) at equivalence ratios of 0.5, 1.0 and 2.0 in ‘air’, and at pressures of 15 and 30 atm. At high-temperatures (> 900 K), the experimental ignition delay times show that the fuel reactivities of 1- and 2-pentene are very similar at all equivalence ratios and pressures. However, at low temperatures, 1-pentene shows negative temperature coefficient behavior and a higher fuel reactivity compared to 2-pentene. Moreover, carbon monoxide time-histories for both 1- and 2-pentene were measured in a high-pressure shock tube for a stoichiometric mixture at 10 atm and at high temperatures. Furthermore, species versus temperature profiles were measured in a jet-stirred reactor at φ = 1.0 and 1 atm over a temperature range of 700–1100 K. All of these experimental data have been used to validate the current chemistry mechanism. Starting from a published pentane mechanism, modifications have been made to the 1- and 2-pentene sub-mechanisms resulting in overall good predictions. Moreover, flux and sensitivity analyses were performed to highlight the important reactions involved in the oxidation process.

Coupling effects of physical and chemical properties on jet fuel spray flame blowout

This work uses an annular co-flow spray burner as a laboratory test method for evaluating one of the important jet fuel figures of merit, namely lean blowout (LBO), and investigates the coupling of physical and chemical properties affecting this phenomenon. Previous work has shown that relative trends in LBO from different fuels in a real gas turbine are well reflected in this burner setup. Representative characteristics for fuel heat of combustion, volatility, atomization, and pressure are used to produce correlations predicting the LBO for this spray burner, thus these characteristics are considered important toward the prediction of LBO in real gas turbine combustors. The results of this testing are compared to general relations for spray flames as published in prior literature; it is found that equivalence ratio at LBO is positively correlated to fuel flow rates and effective evaporation, and inversely correlated to combustion pressure, heat of combustion, and spray droplet diameter. Using simultaneous OH Planar Laser Induced Fluorescence and Mie scattering imaging of the spray and flame structure, the liquid loading in the flame region is also analyzed for surrogate jet fuels which have comparable derived cetane number (DCN) but have very different compositions. Characteristics that can affect the amount of liquid fuel entering the flame region in near-LBO conditions are discussed. The use of surrogates allows for discussion of the competing effects of volatility and reactivity of fuel components. It is found that the most stable flames occur when the interplay of fuel atomization/volatility and reactivity result in substantial penetration of fuel droplets containing components with high DCN.