Theoretical Investigation of Autoignition of Combustible Gas Mixtures in Rapid Compression Machines

2002 ◽  
Author(s):  
Shaoping Shi ◽  
Daniel Lee ◽  
Sandra McSurdy ◽  
Michael McMillian ◽  
Steven Richardson ◽  
...  
Keyword(s):  
Experimental Data ◽  
Theoretical Investigation ◽  
Ignition Delay ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Reaction Scheme ◽  
Independent Manner ◽  
Elementary Reactions ◽  
Chemical Kinetic Mechanism ◽  
Rapid Compression

In any theoretical investigation of ignition processes in natural gas reciprocating engines, physical and chemical mechanisms must be adequately modeled and validated in an independent manner. The Rapid Compression Machine (RCM) has been used in the past as a tool to validate both autoignition models as well as turbulent mixing effects. In this study, two experimental cases were examined. In the first experimental case, the experimental measurements of Lee and Hochgreb (1998a) were chosen to validate the simulation results. In their experiments, hydrogen/oxygen/argon mixtures were used as reactants. In the simulations, a reduced chemical kinetic mechanism consisting of 10 species and 19 elementary reactions coupled to a CFD software, Fluent 6, was used to simulate the autoignition. The ignition delay from the simulation agreed very well with that from the experimental data of Lee and Hochgreb, (1998b). In the second case, experimental data derived from an RCM with two opposed, pneumatically driven pistons (Brett et al., 2001) were used to study the autoignition of methane/oxygen/argon mixtures. The reduced chemical kinetic mechanism DRM22, derived from the GRI-Mech reaction scheme coupled to Fluent 6, was applied in the simulations. The DRM22 scheme included 22 species and 104 reactions. When methane/oxygen/argon mixture were simulated for the RCM, the ignition delay deviated about 15% from the experimental results. The simulation approaches as well as the validation results are discussed in detail in this paper. The paper also discusses an evaluation of reduced reaction models available in the literature for subsequent Fluent modeling.

scholarly journals The Impact of NOx Addition on the Ignition Behavior of N-Pentane

2021 ◽  
Author(s):  
Mark Edward Fuller ◽  
Philipp Morsch ◽  
Franklin Goldsmith ◽  
Karl Alexander Heufer
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Rapid Compression Machine ◽  
Chemical Kinetic Mechanism ◽  
Rapid Compression ◽  
The Impact

This article details new ignition delay time experiments carried out on blends of n-pentane and either NO or NO<sub>2</sub> in the rapid compression machine facility at RWTH Aachen University. Further, a new chemical kinetic mechanism is developed which is able to well-reproduce the experiments and significantly improve over recently published mechanisms. <br>This work has particular value for publication as it adopts a systematic, class-based approach to mechanism development for interactions with nitrogenated species. <br>

scholarly journals The Impact of NOx Addition on the Ignition Behavior of N-Pentane

2021 ◽  
Author(s):  
Mark Edward Fuller ◽  
Philipp Morsch ◽  
Franklin Goldsmith ◽  
Karl Alexander Heufer
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Rapid Compression Machine ◽  
Chemical Kinetic Mechanism ◽  
Rapid Compression ◽  
The Impact

This article details new ignition delay time experiments carried out on blends of n-pentane and either NO or NO<sub>2</sub> in the rapid compression machine facility at RWTH Aachen University. Further, a new chemical kinetic mechanism is developed which is able to well-reproduce the experiments and significantly improve over recently published mechanisms. <br>This work has particular value for publication as it adopts a systematic, class-based approach to mechanism development for interactions with nitrogenated species. <br>

A Numerical Study on the Low Limit Auto-Ignition Temperature of Syngas and Modification of Chemical Kinetic Mechanism

2019 ◽  
Author(s):  
Seung Eon Jang ◽  
Jin Park ◽  
Sang Hyeon Han ◽  
Hong Jip Kim ◽  
Ki Sung Jung ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Region ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Numerical Results ◽  
Auto Ignition ◽  
Chemical Kinetic Mechanism

Abstract In this study, the auto ignition with low limit temperature of syngas has been numerically investigated using a 2-D numerical analysis. Previous study showed that auto ignition was observed at above 860 K in co-flow jet experiments using syngas and dry air. However, the auto ignition at this low temperature range could not be predicted with existing chemical mechanisms. Inconsistency of the auto ignition temperature between the experimental and numerical results is thought to be due to the inaccuracy of the chemical kinetic mechanism. The prediction of ignition delay time and sensitivity analysis for each chemical kinetic mechanism were performed to verify the reasons of the inconsistency between the experimental and numerical results. The results which were calculated using the various mechanisms showed significantly differences in the ignition delay time. In this study, we intend to analyze the reason of discrepancy to predict the auto ignition with low pressure and low temperature region of syngas and to improve the chemical kinetic mechanism. A sensitive analysis has been done to investigate the reaction steps which affected the ignition delay time significantly, and the reaction rate of the selected reaction step was modified. Through the modified chemical kinetic mechanism, we could identify the auto ignition in the low temperature region from the 2-D numerical results. Then CEMA (Chemical Explosive Mode Analysis) was used to validate the 2-D numerical analysis with modified chemical kinetic mechanism. From the validation, the calculated λexp, EI, and PI showed reasonable results, so we expect that the modified chemical kinetic mechanism can be used in various low temperature region.

Mathematical Imaging of Piloted Diffusion Methane-Air Flames Under Anisotropic Scalar Dissipation Rates

2005 ◽  
Author(s):  
Mohsen M. Abou-Ellail ◽  
Karam R. Beshay ◽  
David R. Halka
Keyword(s):  
Diffusion Flame ◽  
Dissipation Rate ◽  
Mixture Fraction ◽  
Flame Temperature ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Scalar Dissipation ◽  
Elementary Reactions ◽  
Chemical Kinetic Mechanism ◽  
Limiting Value

The present work is a numerical simulation of the, piloted, non-premixed, methane–air flame structure in a new mathematical imaging domain. This imaging space has the mixture fraction of diffusion flame Z1 and mixture fraction of pilot flame Z2 as independent coordinates to replace the usual physical space coordinates. The predications are based on the solution of two–dimensional set of transformed second order partial differential conservation equations describing the mass fractions of O2, CH4, CO2, CO, H2O, H2 and sensible enthalpy of the combustion products which are rigorously derived and solved numerically. A three–step chemical kinetic mechanism is adopted. This was deduced in a systematic way from a detailed chemical kinetic mechanism by Peters (1985). The rates for the three reaction steps are related to the rates of the elementary reactions of the full reaction mechanism. The interaction of the pilot flame with the non-premixed flame and the resulting modifications to the structure and chemical kinetics of the flame are studied numerically for different values of the scalar dissipation rate tensor. The dissipation rate tensor represents the flame stretching along Z1, the main mixture fraction, and in the perpendicular direction, along Z2, the pilot mixture fraction. The computed flame temperature contours are plotted in the Z1-Z2 plane for fixed values of the dissipation rate along Z1 and Z2.These temperature contours show that the flame will become unstable when the dissipate rates along Z1 and Z2 increase, simultaneously, to the limiting value for complete flame extinction of 45 s−1. However, the diffusion flame will extinguish for dissipate rates less than 20 1/s, if unpiloted. It is also noticed that the flame will remain stable if the dissipation rate along Z2 is increased to the limiting value, while the dissipation rate, along Z2, remains constant at a value less than 30 s−1.

Exergy parametric study of carbon monoxide oxidation in moist air

2015 ◽  
Vol 40 (4) ◽  
Author(s):  
Ferhat Souidi ◽  
Toufik Benmalek ◽  
Billel Yesaad ◽  
Mouloud Baik
Keyword(s):  
Carbon Monoxide ◽  
Boundary Layer Equation ◽  
Chemical Species ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Premixed Flame ◽  
Moist Air ◽  
Elementary Reactions ◽  
Chemical Kinetic Mechanism ◽  
Oxidation Of Carbon Monoxide

AbstractThis study aims to analyze the oxidation of carbon monoxide in moist air from the second thermodynamic law aspect. A mathematical model of laminar premixed flame in a stagnation point flow has been achieved by numerical solution of the boundary layer equation using a self-made code. The chemical kinetic mechanism for flameless combustion of fuel, which is a mixture of carbon monoxide, oxygen, and water vapor, is modeled by 34 elementary reactions that incorporate (09) nine chemical species:

A study of the dimethyl ether spray characteristics and ignition delay

2007 ◽  
Vol 8 (4) ◽  
pp. 337-346 ◽  
Author(s):  
Y Kim ◽  
J Lim ◽  
K Min
Keyword(s):  
Dimethyl Ether ◽  
Ignition Delay ◽  
Kinetic Mechanism ◽  
Vapour Phase ◽  
Mie Scattering ◽  
Chemical Kinetic ◽  
Spray Angle ◽  
Flamelet Model ◽  
Temperature Conditions ◽  
Chemical Kinetic Mechanism

The characteristics of the spray behaviour and ignition delay of dimethyl ether (DME) were investigated in both experiment and simulation. DME spray images were taken in a constant-volume vessel by using Mie scattering and shadowgraph methods to measure the spray tip penetration and the spray angle of the liquid and vapour phase. The images were acquired at low- and high-temperature conditions and it was found that the spray development was dependent on the ambient density. The ignition delay of DME spray was also measured under high pressure and temperature conditions and compared with that of diesel spray in the same conditions. To predict the ignition and combustion characteristics of DME, a reduced chemical kinetic mechanism consisting of 28 species and 45 reactions was derived from a detailed mechanism. Calculated results in homogeneous conditions agreed well with the measured data from shock tube experiments. Then three-dimensional simulation of spray development and ignition delay of DME spray was performed using a flamelet model associated with a computational fluid dynamics (CFD) code and the reduced chemical kinetic mechanism. The results showed good agreement with the above experimental results.

scholarly journals Chemical Kinetic Mechanism Study on Premixed Combustion of Ammonia/Hydrogen Fuels for Gas Turbine Use

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Hua Xiao ◽  
Agustin Valera-Medina
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Ignition Delay ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Sensitivity Analyses ◽  
Mechanism Study ◽  
Combustion Chemistry ◽  
Chemical Mechanisms ◽  
Ignition Delay Times

To explore the potential of ammonia-based fuel as an alternative fuel for future power generation, studies involving robust mathematical, chemical, thermofluidic analyses are required to progress toward industrial implementation. Thus, the aim of this study is to identify reaction mechanisms that accurately represent ammonia kinetics over a large range of conditions, particularly at industrial conditions. To comprehensively evaluate the performance of the chemical mechanisms, 12 mechanisms are tested in terms of flame speed, NOx emissions and ignition delay against the experimental data. Freely propagating flame calculations indicate that Mathieu mechanism yields the best agreement within experimental data range of different ammonia concentrations, equivalence ratios, and pressures. Ignition delay times calculations show that Mathieu mechanism and Tian mechanism yield the best agreement with data from shock tube experiments at pressures up to 30 atm. Sensitivity analyses were performed in order to identify reactions and ranges of conditions that require optimization in future mechanism development. The present study suggests that the Mathieu mechanism and Tian mechanism are the best suited for the further study on ammonia/hydrogen combustion chemistry under practical industrial conditions. The results obtained in this study also allow gas turbine designers and modelers to choose the most suitable mechanism for combustion studies.

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