A directed relation graph method for mechanism reduction

Lu, Tianfeng; Law, Chung K.

doi:10.1016/j.proci.2004.08.145

Cited by 814 publications

(479 citation statements)

References 17 publications

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“…The DRG 49 method is based on the observation that weakly coupled species during combustion process can be eliminated. The first step in DRG is to quantify species coupling by the pair-wise error, r AB , induced to a species A by the elimination of another species B for a given temperature and species concentrations.…”

Section: Mechanism Reduction With Drgxmentioning

confidence: 99%

Combustion Characteristics of C₅ Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

Park

Chung

et al. 2015

Energy Fuels

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KEYWORDS2-methylbutanol, iso-pentanol, ignition delay, intermediate temperature heat release, skeletal mechanism, HCCI engine combustion 2 ABSTRACT C 5 alcohols are considered alternative fuels because they emit less greenhouse gases and fewer harmful pollutants. In this study, the combustion characteristics of 2-methylbutanol (2-methyl-1-butanol) and iso-pentanol (3-methyl-1-butanol) and their mixtures with primary reference fuels (PRFs) were studied using a detailed chemical kinetic model obtained from merging previously published mechanisms. Ignition delay times of the C 5 alcohol/air mixtures were compared with PRFs at 20 and 40 atm. Reaction path analyses were conducted at intermediate and high temperatures to identify the most influential reactions controlling ignition of C 5 alcohols. The direct relation graph with expert knowledge methodology was used to eliminate unimportant species and reactions in the detailed mechanism, and the resulting skeletal mechanism was tested at various homogeneous charge compression ignition (HCCI) engine combustion conditions. These simulations were used to investigate the heat release characteristics of the methylsubstituted C 5 alcohols, and the results show relatively strong reactions at intermediate temperatures prior to hot ignition. C 5 alcohol blending in PRF75 in HCCI combustion leads to a significant decrease of low temperature heat release (LTHR) and a delay the main combustion.The heat release features demonstrated by C 5 alcohols can be used to improve the design and operation of advanced engine technologies.3

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Section: Mechanism Reduction With Drgxmentioning

confidence: 99%

Combustion Characteristics of C₅ Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

Park

Chung

et al. 2015

Energy Fuels

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“…A gas-phase chemical mechanism with 62 species including pyrene (C 16 H 10 or A4) has been used. This mechanism was reduced from a detailed mechanism (Appel et al 2000) using a directed relation graph (DRG) technique (Lu and Law 2005;Lu et al 2009). Pyrene is treated as the only PAH that participates in soot dynamics.…”

Section: Dns Considerations Using Momicmentioning

confidence: 99%

Development of High Fidelity Soot Aerosol Dynamics Models using Method of Moments with Interpolative Closure

Roy

Arias

Lecoustre

et al. 2014

Aerosol Science and Technology

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The method of moments with interpolative closure (MOMIC) for soot formation and growth provides a detailed modeling framework maintaining a good balance in generality, accuracy, robustness, and computational efficiency. This study presents several computational issues in the development and implementation of the MOMIC-based soot modeling for direct numerical simulations (DNS). The issues of concern include a wide dynamic range of numbers, choice of normalization, high effective Schmidt number of soot particles, and realizability of the soot particle size distribution function (PSDF). These problems are not unique to DNS, but they are often exacerbated by the high-order numerical schemes used in DNS. Four specific issues are discussed in this article: the treatment of soot diffusion, choice of interpolation scheme for MOMIC, an approach to deal with strongly oxidizing environments, and realizability of the PSDF. General, robust, and stable approaches are sought to address these issues, minimizing the use of ad hoc treatments such as clipping. The solutions proposed and demonstrated here are being applied to generate new physical insight into complex turbulence-chemistry-soot-radiation interactions in turbulent reacting flows using DNS.

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“…The major difficulty in its reduction is the large size, for which few methods are feasible because many conventional approaches such as sensitivity analysis become unaffordable when the number of species is larger than a few hundreds. In the present study, the method of direct relation graph (DRG) [25][26][27] was selected to eliminate unimportant species and reactions from the detailed mechanism to obtain a skeletal mechanism that is sufficiently small for the simulation of counterflow ignition.…”

Section: Mechanism Reduction Of Methyl Decanoate With Directed Relatimentioning

confidence: 99%

Experimental and kinetic modeling study of extinction and ignition of methyl decanoate in laminar non-premixed flows

Seshadri

Herbinet

et al. 2009

Proceedings of the Combustion Institute

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Methyl decanoate is a large methyl ester that can be used as a surrogate for biodiesel. In this experimental and computational study, the combustion of methyl decanoate is investigated in nonpremixed, nonuniform flows. Experiments are performed employing the counterflow configuration with a fuel stream made up of vaporized methyl decanoate and nitrogen, and an oxidizer stream of air. The mass fraction of fuel in the fuel stream is measured as a function of the strain rate at extinction, and critical conditions of ignition are measured in terms of the temperature of the oxidizer stream as a function of the strain rate. It is not possible to use a fully detailed mechanism for methyl decanoate to simulate the counterflow flames because the number of species and reactions is too large to employ with current flame codes and computer resources. Therefore a skeletal mechanism was deduced from a detailed mechanism of 8555 elementary reactions and 3036 species using ``directed relation graph'' method. This skeletal mechanism has only 713 elementary reactions and 125 species. Critical conditions of ignition were calculated using this skeletal mechanism and are found to agree well with experimental data. The predicted strain rate at extinction is found to be lower than the measurements. In general, the methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels. Experimental and Kinetic Modeling Study of Extinction and Ignition of Methyl Decanoate in Laminar Nonpremixed Flows Experimental and Kinetic Modeling Study of Extinction and Ignition of Methyl Decanoate in Laminar Nonpremixed Flows AbstractMethyl decanoate is a large methyl ester that can be used as a surrogate for biodiesel. In this experimental and computational study, the combustion of methyl decanoate is investigated in nonpremixed, nonuniform flows. Experiments are performed employing the counterflow configuration with a fuel stream made up of vaporized methyl decanoate and nitrogen, and an oxidizer stream of air. The mass fraction of fuel in the fuel stream is measured as a function of the strain rate at extinction, and critical conditions of ignition are measured in terms of the temperature of the oxidizer stream as a function of the strain rate. It is not possible to use a fully detailed mechanism for methyl decanoate to simulate the counterflow flames because the number of species and reactions is too large to employ with current flame codes and computer resources. Therefore a skeletal mechanism was deduced from a detailed mechanism of 8555 elementary reactions and 3036 species using "directed relation graph" method. This skeletal mechanism has only 713 elementary reactions and 125 species. Critical conditions of ignition were calculated using this skeletal mechanism and are found to agree well with experimental data. The predicted strain rate at extinction is found to be lower than the measurements. In general, the methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

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A directed relation graph method for mechanism reduction

Cited by 814 publications

References 17 publications

Combustion Characteristics of C₅ Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

Combustion Characteristics of C₅ Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

Development of High Fidelity Soot Aerosol Dynamics Models using Method of Moments with Interpolative Closure

Experimental and kinetic modeling study of extinction and ignition of methyl decanoate in laminar non-premixed flows

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A directed relation graph method for mechanism reduction

Cited by 814 publications

References 17 publications

Combustion Characteristics of C5 Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

Combustion Characteristics of C5 Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

Development of High Fidelity Soot Aerosol Dynamics Models using Method of Moments with Interpolative Closure

Experimental and kinetic modeling study of extinction and ignition of methyl decanoate in laminar non-premixed flows

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Combustion Characteristics of C₅ Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation

Combustion Characteristics of C₅ Alcohols and a Skeletal Mechanism for Homogeneous Charge Compression Ignition Combustion Simulation