Experimental Investigation and Analysis of Auto-Ignition Combustion Dynamics

2018 ◽  
Author(s):  
Abhinav Tripathi ◽  
Chen Zhang ◽  
Zongxuan Sun
Keyword(s):  
Ignition Delay ◽  
Internal Combustion Engines ◽  
Path Dependence ◽  
Fuel Mixture ◽  
Reaction Rates ◽  
Chemical Kinetic ◽  
Combustion Dynamics ◽  
Auto Ignition ◽  
Compression And Expansion ◽  
Rapid Compression

From engine controls’ perspective, understanding autoignition dynamics is a key to enabling new combustion modes for internal combustion engines, especially for renewable fuels. Conventional autoignition investigations of fuels commonly involve a rapid compression of oxidizer-fuel mixture to a desired set of temperature-pressure conditions in a rapid compression machine (RCM), and subsequent measurement of the ignition delay. However, even for relatively close thermal states at the compressed condition, different thermodynamic paths (pressure-temperature histories) may lead to significantly different chemical kinetic states and hence significantly different ignition delay measurements. Currently, there exists no systematic method to study this path dependence of auto-ignition. In this work we present, for the first time, a systematic framework for investigation of the effect of small perturbations in the thermo-kinetic states, caused by perturbing the thermodynamic path of compression, on the ignition delay of fuels from a dynamical systems perspective. First, we introduce a novel controlled trajectory rapid compression and expansion machine (CT-RCEM) which offers the ability to precisely control the piston trajectory during compression of the fuel-oxidizer mixture, allowing the thermodynamic path to be tailored as desired. We use the CT-RCEM to experimentally investigate the influence of compression trajectory perturbation on the ignition delay of a specific fuel — dimethyl-ether (DME). Next, using a reduced order model of the combustion dynamics in the CT-RCEM that we developed, we investigate the evolution of the perturbation in the thermo-kinetic states resulting from trajectory perturbation to explain the experimental observations. Finally, we show that the sensitivity of auto-ignition to the thermodynamic path perturbation essentially arises from changes in the chemical reaction rates due to different amounts of intermediate species buildup for different thermodynamic paths.

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.

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.

A Kinetic Investigation of the Role of Changes in the Composition of Natural Gas in Engine Applications

2002 ◽  
Vol 124 (2) ◽  
pp. 404-411 ◽  
Author(s):  
E. B. Khalil ◽  
G. A. Karim
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Combustion Engine ◽  
Kinetic Scheme ◽  
Simulation Models ◽  
Fuel Mixture ◽  
Chemical Kinetic ◽  
Constant Volume ◽  
High Molar Mass ◽  
Fuel Mixtures

The influence of variations in the composition of natural gas on the ignition and combustion processes in engines is investigated. Particular attention is given to changes in the relatively small concentrations of high molar mass alkanes that may be present in the fuel. A detailed chemical kinetic scheme for the oxidation of the higher hydrocarbon components of up to n-heptane was used to investigate analytically the combustion reactions of different fuel mixtures under constant volume adiabatic conditions with initial states that are similar to those during the ignition delay of a typical internal combustion engine. These comprehensive simulation calculations require much computing capacity and time that would preclude their incorporation in full simulation models of engine processes. A simplification is introduced based on replacing artificially the small concentrations of any higher hydrocarbons that may be present in the natural gas by a kinetically equivalent amount of propane in the fuel mixture. This is done such that the resulting equivalent fuel has the same ignition delay as the original fuel under constant volume engine T.D.C. conditions. This “propane equivalent” concept was used in full engine simulation models while employing a relatively short scheme of 150 steps for the oxidation of fuel mixtures of propane, ethane, and methane in air.

Auto Ignition Study of Methane and Bio Alcohol Fuel Blends

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Xuan Zheng ◽  
Shirin Jouzdani ◽  
Benjamin Akih-Kumgeh
Keyword(s):  
Experimental Data ◽  
Kinetic Models ◽  
Ignition Delay ◽  
Chemical Kinetic ◽  
Dual Fuel ◽  
Fuel Blends ◽  
Ignition Delay Times ◽  
Auto Ignition ◽  
Alcohol Fuel ◽  
Delay Times

Abstract Methane (CH4) and bio alcohols have different ignition properties. These have been extensively studied and the resulting experimental data have been used to validate chemical kinetic models. Methane is the main component of natural gas, which is of interest because of its relative availability and lower emissions compared to other hydrocarbon fuels. Given growing interest in fuel-flexible systems, there can be situations in which the combustion properties of natural gas need to be modified by adding biofuels such as bio alcohols. This can occur in dual-fuel internal combustion engines or gas turbines with dual-fuel capabilities. The combustion behavior of such blends can be understood by studying the auto ignition properties in fundamental combustion experiments. Studies of the ignition of such blends are very limited in the literature. In this work, the auto ignition of methane and bio alcohol fuel blends is investigated using a shock tube facility. The chosen bio alcohols are ethanol (C2H5OH) and n-propanol (NC3H7OH). Experiments are carried out at 3 atm and 10 atm for stoichiometric and lean mixtures of fuel, oxygen, and argon. The ignition delay times of the pure fuels are first established at conditions of constant oxygen concentration and comparable pressures. The ignition delay times of blends with 50% methane are then measured. The pyrolysis kinetics of the blends is further explored by measuring CO formation during pyrolysis of the alcohol and methane–alcohol blends. The resulting experimental data are compared with the predictions of selected chemical kinetic models to establish the ability of these models to predict the disproportionate enhancement of methane ignition by the added alcohol.

Auto Ignition Study of Methane and Bio Alcohol Fuel Blends

2019 ◽  
Author(s):  
Xuan Zheng ◽  
Shirin Jouzdani ◽  
Benjamin Akih-Kumgeh
Keyword(s):  
Experimental Data ◽  
Kinetic Models ◽  
Ignition Delay ◽  
Chemical Kinetic ◽  
Dual Fuel ◽  
Fuel Blends ◽  
Ignition Delay Times ◽  
Auto Ignition ◽  
Alcohol Fuel ◽  
Delay Times

Abstract Methane (CH4) and bio alcohols have different ignition properties. These have been extensively studied and the resulting experimental data have been used to validate chemical kinetic models. Methane is the main component of natural gas, which is of interest because of its relative availability and lower emissions compared to other hydrocarbon fuels. Given growing interest in fuel-flexible systems, there can be situations in which the combustion properties of natural gas need to be modified by adding biofuels, such as bio alcohols. This can occur in dual fuel internal combustion engines or gas turbines with dual fuel capabilities. The combustion behavior of such blends can be understood by studying the auto ignition properties in fundamental combustion experiments. Studies of the ignition of such blends are very limited in the literature. In this work, the auto ignition of methane and bio alcohol fuel blends is investigated using a shock tube facility. The chosen bio alcohols are ethanol (C2H5OH) and n-propanol (NC3H7OH). Experiments are carried out at 3 atm and 10 atm for stoichiometric and lean mixtures of fuel, oxygen, and argon. The ignition delay times of the pure fuels are first established at conditions of constant oxygen concentration and comparable pressures. The ignition delay times of blends with 50% methane are then measured. The pyrolysis kinetics of the blends is further explored by measuring CO formation during pyrolysis of the alcohol and methane-alcohol blends. The resulting experimental data are compared with the predictions of selected chemical kinetic models to establish the ability of these models to predict the disproportionate enhancement of methane ignition by the added alcohol.

scholarly journals Study on Characteristics of Auto-ignition and Combustion in Hydrogen Jet with a Rapid Compression and Expansion

2009 ◽  
Vol 4 (2) ◽  
pp. 395-408 ◽  
Author(s):  
Taku TSUJIMURA ◽  
Keita MITSUSHIMA ◽  
Ryuichi HATA ◽  
Yoshiroh TOKUNAGA ◽  
Jiro SENDA ◽  
...  
Keyword(s):  
Auto Ignition ◽  
Compression And Expansion ◽  
Rapid Compression ◽  
Ignition And Combustion

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>

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