The Experts below are selected from a list of 6081 Experts worldwide ranked by ideXlab platform
Yuan Hu - One of the best experts on this subject based on the ideXlab platform.
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comparative investigation on Combustion Property and smoke toxicity of epoxy resin filled with α and δ mno2 nanosheets
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Wei Wang, Yongchun Kan, K M Liew, Lei Song, Yuan HuAbstract:Abstract Manganese dioxide (MnO2) as a promising green material has attracted widely attention in virtue of its outstanding chemical and physical properties. Herein, MnO2 nanosheets with α- and δ- crystal structures were used to comparatively study the influence of crystal structures on the fire resistance of EP resin. Cone calorimeter results confirmed that δ-MnO2 nanosheets achieved better improvements than α-MnO2 nanosheets in reducing the PHRR and THR values as well as suppressing smoke release during Combustion process. Moreover, Raman data and SEM tests showed that δ-MnO2 nanosheets could effectively promote the char dense of char residues of EP composites. TG-IR results also indicated that the pyrolysis toxic products were significantly decreased after the incorporation of δ-MnO2 nanosheets. By the way, the mechanical Property of EP/δ-MnO2 2% composites had no obvious reduction compared with pristine EP resin, which would not restrict the application of EP resin in fields requiring high mechanical properties.
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comparative investigation on Combustion Property and smoke toxicity of epoxy resin filled with α and δ mno2 nanosheets
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Wei Wang, Yongchun Kan, K M Liew, Lei Song, Yuan HuAbstract:Abstract Manganese dioxide (MnO2) as a promising green material has attracted widely attention in virtue of its outstanding chemical and physical properties. Herein, MnO2 nanosheets with α- and δ- crystal structures were used to comparatively study the influence of crystal structures on the fire resistance of EP resin. Cone calorimeter results confirmed that δ-MnO2 nanosheets achieved better improvements than α-MnO2 nanosheets in reducing the PHRR and THR values as well as suppressing smoke release during Combustion process. Moreover, Raman data and SEM tests showed that δ-MnO2 nanosheets could effectively promote the char dense of char residues of EP composites. TG-IR results also indicated that the pyrolysis toxic products were significantly decreased after the incorporation of δ-MnO2 nanosheets. By the way, the mechanical Property of EP/δ-MnO2 2% composites had no obvious reduction compared with pristine EP resin, which would not restrict the application of EP resin in fields requiring high mechanical properties.
Frederick L Dryer - One of the best experts on this subject based on the ideXlab platform.
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reconstruction of chemical structure of real fuel by surrogate formulation based upon Combustion Property targets
Combustion and Flame, 2017Co-Authors: Francis M Haas, Stephen Dooley, Tim Edwards, Frederick L DryerAbstract:Abstract The global chemical character of complex chemical fuel mixtures is explicitly determined by evaluating the abundances of chemical functional groups present within them rather than by applying a traditional interpretation based upon molecular species composition. Statistical analyses of the relationships among each chemical functional group and specific Combustion Property targets (CPTs) of the fuel are rigorously developed. The results demonstrate that the four CPTs currently used in aviation kerosene surrogate formulation - H/C molar ratio, derived cetane number (DCN), average molecular weight (MW), and threshold sooting index (TSI) - effectively constrain the chemical functional group distribution of the fuel, and, hence, the global Combustion behaviors of pre-vaporized fuel/air mixtures. Successful emulation of the CPTs for a target real fuel involves developing a surrogate mixture that defines an “equivalent” chemical functional group distribution to that of the target fuel. Among the CPTs used for real fuel surrogate development, DCN does not abide by a linear blending rule, which generally frustrates development of surrogates. However, a quantitative structure–Property relation (QSPR) regression for DCN is demonstrated here using the chemical functional group approach. Results of the regression reveal that the (CH 2 ) n group plays the most significant role in determining the fuel autoignition propensity, followed by the influences of CH 3 and benzyl-type groups. The QSPR functional group approach extends to provide a powerful tool to address potential preferential vaporization effects dictated by fuel distillation characteristics. Further analysis of fuel chemical Property variation (DCN and H/C ratio) over the distillation curve (and other physical properties) provides a foundation for understanding the complex Combustion behaviors of multi-phase and multi-component fuels relevant to real gas turbine engine applications.
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predicting the global Combustion behaviors of petroleum derived and alternative jet fuels by simple fuel Property measurements
Fuel, 2016Co-Authors: Sang Hee Won, Francis M Haas, Stephen Dooley, Peter S Veloo, Jeffrey Santner, Frederick L DryerAbstract:Abstract Pre-vaporized global Combustion behaviors of a petroleum-derived jet fuel (JP-8), five alternative jet fuels (Shell SPK, Sasol IPK, HRJ Camelina, HRJ Tallow, and Gevo ATJ), and five 50/50 (liquid volume) blends of JP-8/alternative fuels are experimentally examined and compared. Three experiments are performed to investigate the gas-phase Combustion behaviors of the tested fuel samples: (1) global oxidative species profiles in a variable pressure flow reactor, (2) diffusion flame extinction in a counterflow burner, and (3) premixed flame initiation in a heated spherical Combustion chamber. Multivariate linear regression methods have been applied to investigate the sensitivities of pre-vaporized global Combustion behaviors to individual Combustion Property targets of the fuels, including Derived Cetane Number (DCN), H/C ratio, mean molecular weight, and smoke point. As a proof of concept for fuel screening tool based on the standardized fuel Property measurements, a “Combustion Property target (CPT) index” based upon this regression analysis is found to show promise as a rapid means to evaluate the global pre-vaporized Combustion behaviors of the tested fuel samples against each other as well as the spectrum of JP-8 fuels found in use. The present work suggests the applicability of such a methodology not only as an expeditious fuel screening tool for assessing the fully pre-vaporized, kinetically coupled behaviors of emerging alternative jet fuel candidates, but further supports the use of Combustion Property targets in developing kinetic models that are specific to each real fuel.
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emulating the Combustion behavior of real jet aviation fuels by surrogate mixtures of hydrocarbon fluid blends implications for science and engineering
Energy & Fuels, 2014Co-Authors: Frederick L Dryer, Stephen Dooley, Saeed Jahangirian, Joshua S Heyne, Venkatesh Iyer, Thomas A Litzinger, Robert J SantoroAbstract:We have demonstrated previously that a (surrogate fuel) mixture of known pure hydrocarbon species that closely matches four Combustion Property targets (the derived cetane number (DCN), the hydrogen to carbon molar ratio (H/C), the threshold soot index (TSI), and the average molecular weight) of a specific jet fuel, displays fully prevaporized global Combustion kinetic behaviors that are closely consistent. Here, we demonstrate a similar result can be obtained by formulating surrogate hydrocarbon fluid mixtures from distillation cuts of molecular class hydrocarbons or even real gas turbine fuels (for which the specific molecular species classes are no more than qualitatively known). Fully prevaporized chemical reactivities of hydrocarbon fluid surrogate mixtures and real jet fuels are compared using a high pressure flow reactor at 12.5 atm pressure, over the temperature range 500–1000 K, at stoichiometric conditions, and for the same fixed molar carbon content. Results are reported for two different real ...
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reduced kinetic models for the Combustion of jet propulsion fuels
51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013, 2013Co-Authors: Stephen Dooley, Frederick L Dryer, Tanvir Farouk, Sang Hee WonAbstract:Reduced chemical kinetic models to predict the Combustion characteristics of jet propulsion fuels are produced and tested. The parent detailed kinetic model has been developed on the basis of a surrogate fuel formulation methodology that utilizes Combustion Property targets measured for a particular real fuel to formulate a chemical mixture of nalkanes, iso-alkanes and aromatic functionalities to emulate the Combustion behavior of specific target jet aviation fuels. Detailed model predictions are compared against reflected shock ignition delays of both pure components and surrogate fuel mixtures. Systematically reduced models for each individual fuel component are produced and used to test the parent model performance against laminar burning velocity. Finally, a range of systematically reduced kinetic models for two, substantially different, validated surrogate fuels for a particular jet aviation fuel are produce and tested to allow the user a choice in computational cost versus reduced model fidelity. A reduced model of 233 species is produced that closely shares the predictability of the detailed model over the tested conditions. Analysis of the models provides a basis for further refinements in describing the chemical kinetic behavior of all conventional and alternative jet fuels. The limitations of the presented approach are discussed and needs for further refinements are identified.
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the experimental evaluation of a methodology for surrogate fuel formulation to emulate gas phase Combustion kinetic phenomena
Combustion and Flame, 2012Co-Authors: Stephen Dooley, Frederick L Dryer, Sang Hee Won, Joshua S Heyne, Tanvir Farouk, Kamal Kumar, Xin Hui, Chihjen Sung, Haowei Wang, Matthew A OehlschlaegerAbstract:Abstract A methodology for the formulation of surrogate fuels for the emulation of real fuel gas phase Combustion kinetic phenomena pertinent to gas turbine Combustion is described and tested. A mixture of n -dodecane/ iso -octane/1,3,5-trimethylbenzene/ n -propylbenzene is formulated in a predictive manner to exhibit the same gas phase Combustion phenomena of a target Jet-A fuel by the sharing of fundamentally significant Combustion Property targets in addition to a prescribed commonality of chemical kinetically controlling intermediate species. The appropriateness of the surrogate formulation technique is demonstrated by the experimental measurement of various gas phase Combustion kinetic phenomena of the proposed surrogate mixture and of the target Jet-A fuel: (1) A variable pressure flow reactor is used to chart the chemical reactivity of a stoichiometric mixture of surrogate fuel/O 2 /N 2 at 12.5 atm and 500–1000 K, for a residence time of 1.8 s at a fixed carbon content of 0.3%. (2) The autoignition behavior of stoichiometric mixtures of surrogate fuel in air is measured with a shock tube at 667–1223 K at ∼20 atm and also with a rapid compression machine at 645–714 K at compressed pressures of 21.7 atm. (3) Detailed measurements of the intermediate species formed in the high temperature oxidation of the target fuel and in the oxidation of the surrogate fuel are performed with a shock tube for reaction times of 1.23–3.53 ms at 18–35 atm and 901–1760 K for 0.0808/0.158/0.1187 mole% mixtures of C/H/O 2 . (4) The laminar burning velocity and strain extinction limits of premixed mixtures of surrogate fuel in O 2 /N 2 are determined by the counter flow twin flame technique. These phenomena are also determined for premixed mixtures of the target fuel and for a previously proposed surrogate fuel composed of n -decane/ iso -octane/toluene in O 2 /N 2 . (5) The high temperature chemical reactivity and chemical kinetic–molecular diffusion coupling of the surrogate fuel is evaluated by measurement of the strained extinction limits of diffusion flames. (6) The propensity of surrogate and real fuel to form soot is tested by laser extinction measurements of the soot volume fractions formed by each fuel in a wick-fed laminar flame diffusion burner as a function of the radial distance of each flame. These experimental data are compared to those previously reported at identical conditions for the target Jet-A fuel and for a similar n -decane/ iso -octane/toluene surrogate fuel. A conceptual theory of real fuel oxidation is proposed and the similarity of the exhibited Combustion phenomena of all three fuels is analyzed and interpreted in this context in order to (a) further evaluate the proposed strategy to surrogate fuel formulation and the appropriateness of the proposed theory to real fuel oxidation, (b) evaluate the appropriateness of the proposed n -dodecane/ iso -octane/1,3,5-trimethylbenzene/ n -propylbenzene mixture as a surrogate fuel for the target Jet-A fuel, and (c) to provide direction for the development of a tractable numerical modeling framework to compute real fuel multiphase Combustion phenomena.
Wei Wang - One of the best experts on this subject based on the ideXlab platform.
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comparative investigation on Combustion Property and smoke toxicity of epoxy resin filled with α and δ mno2 nanosheets
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Wei Wang, Yongchun Kan, K M Liew, Lei Song, Yuan HuAbstract:Abstract Manganese dioxide (MnO2) as a promising green material has attracted widely attention in virtue of its outstanding chemical and physical properties. Herein, MnO2 nanosheets with α- and δ- crystal structures were used to comparatively study the influence of crystal structures on the fire resistance of EP resin. Cone calorimeter results confirmed that δ-MnO2 nanosheets achieved better improvements than α-MnO2 nanosheets in reducing the PHRR and THR values as well as suppressing smoke release during Combustion process. Moreover, Raman data and SEM tests showed that δ-MnO2 nanosheets could effectively promote the char dense of char residues of EP composites. TG-IR results also indicated that the pyrolysis toxic products were significantly decreased after the incorporation of δ-MnO2 nanosheets. By the way, the mechanical Property of EP/δ-MnO2 2% composites had no obvious reduction compared with pristine EP resin, which would not restrict the application of EP resin in fields requiring high mechanical properties.
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comparative investigation on Combustion Property and smoke toxicity of epoxy resin filled with α and δ mno2 nanosheets
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Wei Wang, Yongchun Kan, K M Liew, Lei Song, Yuan HuAbstract:Abstract Manganese dioxide (MnO2) as a promising green material has attracted widely attention in virtue of its outstanding chemical and physical properties. Herein, MnO2 nanosheets with α- and δ- crystal structures were used to comparatively study the influence of crystal structures on the fire resistance of EP resin. Cone calorimeter results confirmed that δ-MnO2 nanosheets achieved better improvements than α-MnO2 nanosheets in reducing the PHRR and THR values as well as suppressing smoke release during Combustion process. Moreover, Raman data and SEM tests showed that δ-MnO2 nanosheets could effectively promote the char dense of char residues of EP composites. TG-IR results also indicated that the pyrolysis toxic products were significantly decreased after the incorporation of δ-MnO2 nanosheets. By the way, the mechanical Property of EP/δ-MnO2 2% composites had no obvious reduction compared with pristine EP resin, which would not restrict the application of EP resin in fields requiring high mechanical properties.
Lei Song - One of the best experts on this subject based on the ideXlab platform.
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comparative investigation on Combustion Property and smoke toxicity of epoxy resin filled with α and δ mno2 nanosheets
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Wei Wang, Yongchun Kan, K M Liew, Lei Song, Yuan HuAbstract:Abstract Manganese dioxide (MnO2) as a promising green material has attracted widely attention in virtue of its outstanding chemical and physical properties. Herein, MnO2 nanosheets with α- and δ- crystal structures were used to comparatively study the influence of crystal structures on the fire resistance of EP resin. Cone calorimeter results confirmed that δ-MnO2 nanosheets achieved better improvements than α-MnO2 nanosheets in reducing the PHRR and THR values as well as suppressing smoke release during Combustion process. Moreover, Raman data and SEM tests showed that δ-MnO2 nanosheets could effectively promote the char dense of char residues of EP composites. TG-IR results also indicated that the pyrolysis toxic products were significantly decreased after the incorporation of δ-MnO2 nanosheets. By the way, the mechanical Property of EP/δ-MnO2 2% composites had no obvious reduction compared with pristine EP resin, which would not restrict the application of EP resin in fields requiring high mechanical properties.
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comparative investigation on Combustion Property and smoke toxicity of epoxy resin filled with α and δ mno2 nanosheets
Composites Part A-applied Science and Manufacturing, 2018Co-Authors: Wei Wang, Yongchun Kan, K M Liew, Lei Song, Yuan HuAbstract:Abstract Manganese dioxide (MnO2) as a promising green material has attracted widely attention in virtue of its outstanding chemical and physical properties. Herein, MnO2 nanosheets with α- and δ- crystal structures were used to comparatively study the influence of crystal structures on the fire resistance of EP resin. Cone calorimeter results confirmed that δ-MnO2 nanosheets achieved better improvements than α-MnO2 nanosheets in reducing the PHRR and THR values as well as suppressing smoke release during Combustion process. Moreover, Raman data and SEM tests showed that δ-MnO2 nanosheets could effectively promote the char dense of char residues of EP composites. TG-IR results also indicated that the pyrolysis toxic products were significantly decreased after the incorporation of δ-MnO2 nanosheets. By the way, the mechanical Property of EP/δ-MnO2 2% composites had no obvious reduction compared with pristine EP resin, which would not restrict the application of EP resin in fields requiring high mechanical properties.
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Effects of ferric chloride on structure, surface morphology and Combustion Property of electrospun polyacrylonitrile composite nanofibers
Fibers and Polymers, 2011Co-Authors: Yibing Cai, Lei Song, Dawei Gao, Qufu Wei, Shi Zhou, Fenglin Huang, Weidong GaoAbstract:In this work, the pure polyacrylonitrile (PAN) nanofibers and PAN/FeCl3 composite nanofibers were prepared by an electrospinning process. Electrospinning solution properties including viscosity, surface tension and conductivity, had been measured and combined with the results of Scanning electron microscopy (SEM), Atomic force microscope (AFM) and Micro Combustion Calorimeter (MCC) to investigate the effects of FeCl3 on the structure, surface morphology and Combustion Property of electrospun PAN nanofibers, respectively. It was found from SEM images that the diameters of composite nanofibers were decreased with the addition of FeCl3, which was attributed predominantly to the increased conductivity of the polymer solutions compared to viscosity and surface tension. The AFM analyses revealed that the surface morphology of electrospun nanofibers changed from smooth and wrinkle-like structure (without FeCl3) to rough and ridge-like structure (with FeCl3). The results characterized by MCC showed that the loading of FeCl3 decreased the heat release rate (HRR) and improved the Combustion Property of composite nanofibers.
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study on Combustion Property and synergistic effect of intumescent flame retardant styrene butadiene rubber with metallic oxides
Polymers for Advanced Technologies, 2009Co-Authors: Qingqing Liu, Lei Song, Zhengzhou Wang, Shun ZhouAbstract:Effect of metallic oxides on flame retardancy and the thermal stability of styrene butadiene rubber (SBR) composites based on ammonium polyphosphate (APP) and pentaerythritol (PER) was studied by the limiting oxygen index (LOI), UL 94, the cone calorimeter tests, and thermogravimetry analysis (TGA), respectively. Scanning electron microscopy (SEM) and wide-angle X-ray diffraction (WAXD) were used to analyze the morphological structure and the component of the residue chars formed from the SBR composites accordingly. The addition of zirconium dioxide (ZrO2) at a loading of 3.4 phr could improve the UL 94 test rating of the composite to V-0. The TGA data illustrated that the metallic oxides could enhance the thermal stability of the SBR/Intumescent flame retardant additives (IFRs) composites at high temperature and increase the residue. Cone calorimeter test gave much clear evidence that the incorporation of ZrO2 into SBR/IFRs composites resulted in the significant deduction of the heat release rate (HRR) values, and the SEM images showed that the char layers of the composites containing the metallic oxides became more compact. From the WAXD pattern, zirconium phosphate (ZrP2O7) may be formed by the reaction between ZrO2 and APP. Due to the addition of ZrO2 and the formation of ZrP2O7, the flame retardancy of the composite was improved. Copyright © 2009 John Wiley & Sons, Ltd.
Stephen Dooley - One of the best experts on this subject based on the ideXlab platform.
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reconstruction of chemical structure of real fuel by surrogate formulation based upon Combustion Property targets
Combustion and Flame, 2017Co-Authors: Francis M Haas, Stephen Dooley, Tim Edwards, Frederick L DryerAbstract:Abstract The global chemical character of complex chemical fuel mixtures is explicitly determined by evaluating the abundances of chemical functional groups present within them rather than by applying a traditional interpretation based upon molecular species composition. Statistical analyses of the relationships among each chemical functional group and specific Combustion Property targets (CPTs) of the fuel are rigorously developed. The results demonstrate that the four CPTs currently used in aviation kerosene surrogate formulation - H/C molar ratio, derived cetane number (DCN), average molecular weight (MW), and threshold sooting index (TSI) - effectively constrain the chemical functional group distribution of the fuel, and, hence, the global Combustion behaviors of pre-vaporized fuel/air mixtures. Successful emulation of the CPTs for a target real fuel involves developing a surrogate mixture that defines an “equivalent” chemical functional group distribution to that of the target fuel. Among the CPTs used for real fuel surrogate development, DCN does not abide by a linear blending rule, which generally frustrates development of surrogates. However, a quantitative structure–Property relation (QSPR) regression for DCN is demonstrated here using the chemical functional group approach. Results of the regression reveal that the (CH 2 ) n group plays the most significant role in determining the fuel autoignition propensity, followed by the influences of CH 3 and benzyl-type groups. The QSPR functional group approach extends to provide a powerful tool to address potential preferential vaporization effects dictated by fuel distillation characteristics. Further analysis of fuel chemical Property variation (DCN and H/C ratio) over the distillation curve (and other physical properties) provides a foundation for understanding the complex Combustion behaviors of multi-phase and multi-component fuels relevant to real gas turbine engine applications.
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predicting the global Combustion behaviors of petroleum derived and alternative jet fuels by simple fuel Property measurements
Fuel, 2016Co-Authors: Sang Hee Won, Francis M Haas, Stephen Dooley, Peter S Veloo, Jeffrey Santner, Frederick L DryerAbstract:Abstract Pre-vaporized global Combustion behaviors of a petroleum-derived jet fuel (JP-8), five alternative jet fuels (Shell SPK, Sasol IPK, HRJ Camelina, HRJ Tallow, and Gevo ATJ), and five 50/50 (liquid volume) blends of JP-8/alternative fuels are experimentally examined and compared. Three experiments are performed to investigate the gas-phase Combustion behaviors of the tested fuel samples: (1) global oxidative species profiles in a variable pressure flow reactor, (2) diffusion flame extinction in a counterflow burner, and (3) premixed flame initiation in a heated spherical Combustion chamber. Multivariate linear regression methods have been applied to investigate the sensitivities of pre-vaporized global Combustion behaviors to individual Combustion Property targets of the fuels, including Derived Cetane Number (DCN), H/C ratio, mean molecular weight, and smoke point. As a proof of concept for fuel screening tool based on the standardized fuel Property measurements, a “Combustion Property target (CPT) index” based upon this regression analysis is found to show promise as a rapid means to evaluate the global pre-vaporized Combustion behaviors of the tested fuel samples against each other as well as the spectrum of JP-8 fuels found in use. The present work suggests the applicability of such a methodology not only as an expeditious fuel screening tool for assessing the fully pre-vaporized, kinetically coupled behaviors of emerging alternative jet fuel candidates, but further supports the use of Combustion Property targets in developing kinetic models that are specific to each real fuel.
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emulating the Combustion behavior of real jet aviation fuels by surrogate mixtures of hydrocarbon fluid blends implications for science and engineering
Energy & Fuels, 2014Co-Authors: Frederick L Dryer, Stephen Dooley, Saeed Jahangirian, Joshua S Heyne, Venkatesh Iyer, Thomas A Litzinger, Robert J SantoroAbstract:We have demonstrated previously that a (surrogate fuel) mixture of known pure hydrocarbon species that closely matches four Combustion Property targets (the derived cetane number (DCN), the hydrogen to carbon molar ratio (H/C), the threshold soot index (TSI), and the average molecular weight) of a specific jet fuel, displays fully prevaporized global Combustion kinetic behaviors that are closely consistent. Here, we demonstrate a similar result can be obtained by formulating surrogate hydrocarbon fluid mixtures from distillation cuts of molecular class hydrocarbons or even real gas turbine fuels (for which the specific molecular species classes are no more than qualitatively known). Fully prevaporized chemical reactivities of hydrocarbon fluid surrogate mixtures and real jet fuels are compared using a high pressure flow reactor at 12.5 atm pressure, over the temperature range 500–1000 K, at stoichiometric conditions, and for the same fixed molar carbon content. Results are reported for two different real ...
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reduced kinetic models for the Combustion of jet propulsion fuels
51st AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition 2013, 2013Co-Authors: Stephen Dooley, Frederick L Dryer, Tanvir Farouk, Sang Hee WonAbstract:Reduced chemical kinetic models to predict the Combustion characteristics of jet propulsion fuels are produced and tested. The parent detailed kinetic model has been developed on the basis of a surrogate fuel formulation methodology that utilizes Combustion Property targets measured for a particular real fuel to formulate a chemical mixture of nalkanes, iso-alkanes and aromatic functionalities to emulate the Combustion behavior of specific target jet aviation fuels. Detailed model predictions are compared against reflected shock ignition delays of both pure components and surrogate fuel mixtures. Systematically reduced models for each individual fuel component are produced and used to test the parent model performance against laminar burning velocity. Finally, a range of systematically reduced kinetic models for two, substantially different, validated surrogate fuels for a particular jet aviation fuel are produce and tested to allow the user a choice in computational cost versus reduced model fidelity. A reduced model of 233 species is produced that closely shares the predictability of the detailed model over the tested conditions. Analysis of the models provides a basis for further refinements in describing the chemical kinetic behavior of all conventional and alternative jet fuels. The limitations of the presented approach are discussed and needs for further refinements are identified.
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the experimental evaluation of a methodology for surrogate fuel formulation to emulate gas phase Combustion kinetic phenomena
Combustion and Flame, 2012Co-Authors: Stephen Dooley, Frederick L Dryer, Sang Hee Won, Joshua S Heyne, Tanvir Farouk, Kamal Kumar, Xin Hui, Chihjen Sung, Haowei Wang, Matthew A OehlschlaegerAbstract:Abstract A methodology for the formulation of surrogate fuels for the emulation of real fuel gas phase Combustion kinetic phenomena pertinent to gas turbine Combustion is described and tested. A mixture of n -dodecane/ iso -octane/1,3,5-trimethylbenzene/ n -propylbenzene is formulated in a predictive manner to exhibit the same gas phase Combustion phenomena of a target Jet-A fuel by the sharing of fundamentally significant Combustion Property targets in addition to a prescribed commonality of chemical kinetically controlling intermediate species. The appropriateness of the surrogate formulation technique is demonstrated by the experimental measurement of various gas phase Combustion kinetic phenomena of the proposed surrogate mixture and of the target Jet-A fuel: (1) A variable pressure flow reactor is used to chart the chemical reactivity of a stoichiometric mixture of surrogate fuel/O 2 /N 2 at 12.5 atm and 500–1000 K, for a residence time of 1.8 s at a fixed carbon content of 0.3%. (2) The autoignition behavior of stoichiometric mixtures of surrogate fuel in air is measured with a shock tube at 667–1223 K at ∼20 atm and also with a rapid compression machine at 645–714 K at compressed pressures of 21.7 atm. (3) Detailed measurements of the intermediate species formed in the high temperature oxidation of the target fuel and in the oxidation of the surrogate fuel are performed with a shock tube for reaction times of 1.23–3.53 ms at 18–35 atm and 901–1760 K for 0.0808/0.158/0.1187 mole% mixtures of C/H/O 2 . (4) The laminar burning velocity and strain extinction limits of premixed mixtures of surrogate fuel in O 2 /N 2 are determined by the counter flow twin flame technique. These phenomena are also determined for premixed mixtures of the target fuel and for a previously proposed surrogate fuel composed of n -decane/ iso -octane/toluene in O 2 /N 2 . (5) The high temperature chemical reactivity and chemical kinetic–molecular diffusion coupling of the surrogate fuel is evaluated by measurement of the strained extinction limits of diffusion flames. (6) The propensity of surrogate and real fuel to form soot is tested by laser extinction measurements of the soot volume fractions formed by each fuel in a wick-fed laminar flame diffusion burner as a function of the radial distance of each flame. These experimental data are compared to those previously reported at identical conditions for the target Jet-A fuel and for a similar n -decane/ iso -octane/toluene surrogate fuel. A conceptual theory of real fuel oxidation is proposed and the similarity of the exhibited Combustion phenomena of all three fuels is analyzed and interpreted in this context in order to (a) further evaluate the proposed strategy to surrogate fuel formulation and the appropriateness of the proposed theory to real fuel oxidation, (b) evaluate the appropriateness of the proposed n -dodecane/ iso -octane/1,3,5-trimethylbenzene/ n -propylbenzene mixture as a surrogate fuel for the target Jet-A fuel, and (c) to provide direction for the development of a tractable numerical modeling framework to compute real fuel multiphase Combustion phenomena.