A Reduced Diesel Surrogate Mechanism for Compression Ignition Engine Applications

2012 ◽  
Author(s):  
Mandhapati Raju ◽  
Mingjie Wang ◽  
P. K. Senecal ◽  
Sibendu Som ◽  
Douglas E. Longman
Keyword(s):  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Computational Time ◽  
Zone Model ◽  
Compression Ignition ◽  
Ambient Conditions ◽  
Compression Ignition Engine ◽  
Detailed Mechanism ◽  
Skeletal Mechanism

A skeletal mechanism with 117 species and 472 reactions for a Diesel surrogate i.e., n-heptane, was developed. The detailed mechanism for n-heptane created by Lawrence Livermore National Laboratory (LLNL) was employed as the starting mechanism. The detailed mechanism was then reduced with an enhancement of the Direct Relation Graph (DRG) technique called Parallel DRG-with Error Propagation and Sensitivity Analysis (PDRGEPSA). The reduction was performed for pressures from 20 to 80 atm, equivalence ratios from 0.5 to 2, and an initial temperature range of 600–1200 K, covering the compression ignition (CI) engine conditions. Extensive validations were performed against both 0-D simulations with the detailed mechanism and experimental data for spatially homogeneous systems. In order to perform three-dimensional turbulent spray-combustion and engine simulations, the mechanism was integrated with the multi-zone model in the CONVERGE CFD software to accelerate the calculation of detailed chemical kinetics. The Engine Combustion Network (ECN) data from Sandia National Laboratory was used for validation purposes along with single-cylinder Caterpillar engine data. The skeletal mechanism was able to predict various combustion characteristics accurately such as ignition delay and flame lift-off length (LOL) under different ambient conditions. The performance of the multi-zone solver with respect to the full cell-by-cell chemistry solver (SAGE) is compared for the Caterpillar engine simulation and a good match is obtained with significant speed-up of computational time for the multi-zone solver.

scholarly journals Construction of a reduced mechanism for diesel-natural gas -hydrogen using HCCI model with Direct Relation Graph and Sensitivity Analysis

2020 ◽  
Vol 22 (4) ◽  
pp. 55-60
Author(s):  
Zhao Rui ◽  
Xu Leping ◽  
Feng Shiquan
Keyword(s):  
Sensitivity Analysis ◽  
Laminar Flame ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Direct Relation ◽  
Elementary Reactions ◽  
Detailed Mechanism ◽  
Reduced Mechanism ◽  
Relation Graph ◽  
Skeletal Mechanism

AbstractBased on the theory of direct relation graph (DRG) and sensitivity analysis (SA), a reduced mechanism for diesel-CH4-H2 tri-fuel is constructed. The detailed mechanism of Lawrence Livermore National Laboratory, which has 654 elements and 2827 elementary reactions, is used for mechanism reduction with DRG. Some small thresholds are used in the process of simplifying the detailed mechanism via DRG, and a skeletal mechanism of 266 elements is obtained. Based on the framework of the skeletal mechanism, the time-consuming approach of sensitivity analysis is used for further simplification, and the skeletal mechanism is reduced to 262 elements. Validation of the reduced mechanism is done via a comparison of ignition delay time and laminar flame speed from the calculation using the reduced mechanism and the detailed mechanism or experiment. The reduced mechanism shows good agreement with the detailed mechanism and with related experimental data.

scholarly journals A Multicomponent Blend as a Diesel Fuel Surrogate for Compression Ignition Engine Applications

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Yuanjiang Pei ◽  
Marco Mehl ◽  
Wei Liu ◽  
Tianfeng Lu ◽  
William J. Pitz ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Flow Reactor ◽  
Expert Knowledge ◽  
Combustion Model ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Combined Mechanism ◽  
Fuel Surrogate ◽  
Skeletal Mechanism

A mixture of n-dodecane and m-xylene is investigated as a diesel fuel surrogate for compression ignition (CI) engine applications. Compared to neat n-dodecane, this binary mixture is more representative of diesel fuel because it contains an alkyl-benzene which represents an important chemical class present in diesel fuels. A detailed multicomponent mechanism for n-dodecane and m-xylene was developed by combining a previously developed n-dodecane mechanism with a recently developed mechanism for xylenes. The xylene mechanism is shown to reproduce experimental ignition data from a rapid compression machine (RCM) and shock tube (ST), speciation data from the jet stirred reactor and flame speed data. This combined mechanism was validated by comparing predictions from the model with experimental data for ignition in STs and for reactivity in a flow reactor. The combined mechanism, consisting of 2885 species and 11,754 reactions, was reduced to a skeletal mechanism consisting 163 species and 887 reactions for 3D diesel engine simulations. The mechanism reduction was performed using directed relation graph (DRG) with expert knowledge (DRG-X) and DRG-aided sensitivity analysis (DRGASA) at a fixed fuel composition of 77% of n-dodecane and 23% m-xylene by volume. The sample space for the reduction covered pressure of 1–80 bar, equivalence ratio of 0.5–2.0, and initial temperature of 700–1600 K for ignition. The skeletal mechanism was compared with the detailed mechanism for ignition and flow reactor predictions. Finally, the skeletal mechanism was validated against a spray flame dataset under diesel engine conditions documented on the engine combustion network (ECN) website. These multidimensional simulations were performed using a representative interactive flame (RIF) turbulent combustion model. Encouraging results were obtained compared to the experiments with regard to the predictions of ignition delay and lift-off length at different ambient temperatures.

Multi-zone model for reactivity controlled compression ignition engine based on CFD approach

Energy ◽  
2018 ◽  
Vol 156 ◽  
pp. 213-228 ◽  
Author(s):  
S. Mehdi Lashkarpour ◽  
Rahim Khoshbakhti Saray ◽  
Mohammad Najafi
Keyword(s):  
Zone Model ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Reactivity Controlled Compression Ignition

scholarly journals Lawrence Livermore National Laboratory's activities to achieve ignition by X-ray drive on the National Ignition Facility

1999 ◽  
Vol 17 (2) ◽  
pp. 159-171 ◽  
Author(s):  
J.D. KILKENNY ◽  
T.P. BERNAT ◽  
B.A. HAMMEL ◽  
R.L. KAUFFMAN ◽  
O.L. LANDEN ◽  
...  
Keyword(s):  
Inertial Confinement Fusion ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Department Of Energy ◽  
Naval Research ◽  
Inertial Confinement ◽  
National Ignition Facility ◽  
X Ray ◽  
Omega Laser

The National Ignition Facility (NIF) is a MJ-class glass laser-based facility funded by the Department of Energy which has achieved thermonuclear ignition and moderate gain as one of its main objectives. In the summer of 1998, the project was about 40% complete, and design and construction was on schedule and on cost. The NIF will start firing onto targets in 2001, and will achieve full energy in 2004. The Lawrence Livermore National Laboratory (LLNL) together with the Los Alamos National Laboratory (LANL) have the main responsibility for achieving X-ray driven ignition on the NIF. In the 1990s, a comprehensive series of experiments on Nova at LLNL, followed by recent experiments on the Omega laser at the University of Rochester, demonstrated confidence in understanding the physics of X-ray drive implosions. The same physics at equivalent scales is used in calculations to predict target performance on the NIF, giving credence to calculations of ignition on the NIF. An integrated program of work in preparing the NIF for X-ray driven ignition in about 2007, and the key issues being addressed on the current Inertial Confinement Fusion (ICF) facilities [(Nova, Omega, Z at Sandia National Laboratory (SNL) and NIKE at the Naval Research Laboratory (NRL)], are described.

Experimental and Numerical Study on Auto-Ignition and Combustion of Homogeneous Charge Compression Ignition Fueled With Dimethyl Ether

2005 ◽  
Author(s):  
Ma-Ji Luo ◽  
Zhen Huang ◽  
De-Gang Li
Keyword(s):  
Diesel Engine ◽  
Dimethyl Ether ◽  
Homogeneous Charge Compression Ignition ◽  
Numerical Study ◽  
National Laboratory ◽  
Zone Model ◽  
Compression Ignition ◽  
Hcci Combustion ◽  
Key Species ◽  
Homogeneous Charge

Experimental study of the autoignition and combustion characteristics of homogeneous charge compression ignition (HCCI) was carried out on a modified diesel engine fuelled with Dimethyl ether (DME) fuel. Numerical simulations were also performed by using the detailed chemical kinetic mechanism of DME oxidation proposed by American Lawrence Livermore National Laboratory (LLNL). The experimental results indicate that HCCI combustion with DME fuel can be realized in diesel engine with a few modifications, and it has a two-stage heat release characteristics. The emissions of HCCI combustion with DME fuel can be characterized by free of smoke and near zero NOx. The simulation results suggest that the single-zone model can accurately predict the ignition timings, including the low temperature ignition and high temperature ignition. The variations of key species (such as H2O2, CH2O, OH, HCO, CH, etc) with crank angle during fuel oxidation and the effects of engine operating parameters on HCCI combustion can also be analyzed by numerical simulation.

scholarly journals A Multi-Component Blend as a Diesel Fuel Surrogate for Compression Ignition Engine Applications

2014 ◽  
Author(s):  
Yuanjiang Pei ◽  
Marco Mehl ◽  
Wei Liu ◽  
Tianfeng Lu ◽  
William J. Pitz ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Flow Reactor ◽  
Expert Knowledge ◽  
Combustion Model ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Combined Mechanism ◽  
Fuel Surrogate ◽  
Skeletal Mechanism

A mixture of n-dodecane and m-xylene is investigated as a diesel fuel surrogate for compression ignition engine applications. Compared to neat n-dodecane, this binary mixture is more representative of diesel fuel because it contains an alkyl-benzene which represents an important chemical class present in diesel fuels. A detailed multi-component mechanism for n-dodecane and m-xylene was developed by combining a previously developed n-dodecane mechanism with a recently developed mechanism for xylenes. The xylene mechanism is shown to reproduce experimental ignition data from a rapid compression machine and shock tube, speciation data from the jet stirred reactor and flame speed data. This combined mechanism was validated by comparing predictions from the model with experimental data for ignition in shock tubes and for reactivity in a flow reactor. The combined mechanism, consisting of 2885 species and 11754 reactions, was reduced to a skeletal mechanism consisting 163 species and 887 reactions for 3D diesel engine simulations. The mechanism reduction was performed using directed relation graph (DRG) with expert knowledge (DRG-X) and DRG-aided sensitivity analysis (DRGASA) at a fixed fuel composition of 77% of n-dodecane and 23% m-xylene by volume. The sample space for the reduction covered pressure of 1–80 bar, equivalence ratio of 0.5–2.0, and initial temperature of 700–1600 K for ignition. The skeletal mechanism was compared with the detailed mechanism for ignition and flow reactor predictions. Finally, the skeletal mechanism was validated against a spray flame dataset under diesel engine conditions documented on the Engine Combustion Network (ECN) website. These multi-dimensional simulations were performed using a Representative Interactive Flame (RIF) turbulent combustion model. Encouraging results were obtained compared to the experiments with regards to the predictions of ignition delay and lift-off length at different ambient temperatures.

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