A comprehensive experimental and modeling study of the ignition delay time characteristics of ternary and quaternary blends of methane, ethane, ethylene, and propane over a wide range of temperature, pressure, equivalence ratio, and dilution

The change in laminar burning speed and ignition delay time of iso-octane with the addition of oxygenated fuels are investigated. As oxygenated fuels, ethanol and 2,5 dimethyle furan (DMF) are used. To confirm the process and mechanism a detailed validation is done on laminar burning speed and ignition delay time. Further, three different blending ratios of 5%, 25% and 50% for both ethanol/iso-octane and DMF/iso-octane are investigated separately. Wide range of equivalence ratio from 0.6–1.4 is considered in calculating laminar burning speed. Ignition delay time is measured under various temperatures from 650 K to 1100 K. Results of each blending are compared with the pure fuels. A comparison is also done between the effects of these two oxygenates. It has found that for each blending case presence of DMF brings larger change in the behavior of iso-octane than ethanol. This observation refers to further study on comparison of these two oxygenates.

Download Full-text

Ignition Studies of C1–C7 Natural Gas Blends at Gas-Turbine Relevant Conditions

Volume 4B: Combustion, Fuels, and Emissions ◽

10.1115/gt2020-15826 ◽

2020 ◽

Author(s):

Amrit Bikram Sahu ◽

A. Abd El-Sabor Mohamed ◽

Snehasish Panigrahy ◽

Gilles Bourque ◽

Henry Curran

Keyword(s):

Natural Gas ◽

Gas Turbine ◽

Ignition Delay ◽

Delay Time ◽

Ignition Delay Time ◽

Gas Mixtures ◽

Auto Ignition ◽

Wide Range ◽

Detailed Kinetic Model ◽

Sensitization Effect

Abstract New ignition delay time measurements of natural gas mixtures enriched with small amounts of n-hexane and n-heptane were performed in a rapid compression machine to interpret the sensitization effect of heavier hydrocarbons on auto-ignition at gas-turbine relevant conditions. The experimental data of natural gas mixtures containing alkanes from methane to n-heptane were carried out over a wide range of temperatures (840–1050 K), pressures (20–30 bar), and equivalence ratios (φ = 0.5 and 1.5). The experiments were complimented with numerical simulations using a detailed kinetic model developed to investigate the effect of n-hexane and n-heptane additions. Model predictions show that the addition of even small amounts (1–2%) of n-hexane and n-heptane can lead to increase in reactivity by ∼40–60 ms at compressed temperature (TC) = 700 K. The ignition delay time (IDT) of these mixtures decrease rapidly with an increase in concentration of up to 7.5% but becomes almost independent of the C6/C7 concentration beyond 10%. This sensitization effect of C6 and C7 is also found to be more pronounced in the temperature range 700–900 K compared to that at higher temperatures (> 900 K). The reason is attributed to the dependence of IDT primarily on H2O2(+M) ↔ 2ȮH(+M) at higher temperatures while the fuel dependent reactions such as H-atom abstraction, RȮ2 dissociation or Q.OOH + O2 reactions are less important compared to 700–900 K, where they are very important.

Download Full-text

A Comprehensive Experimental and Simulation Study of Ignition Delay Time Characteristics of Single Fuel C1–C2 Hydrocarbons over a Wide Range of Temperatures, Pressures, Equivalence Ratios, and Dilutions

Energy & Fuels ◽

10.1021/acs.energyfuels.9b04139 ◽

2020 ◽

Vol 34 (3) ◽

pp. 3755-3771 ◽

Cited By ~ 8

Author(s):

Mohammadreza Baigmohammadi ◽

Vaibhav Patel ◽

Sergio Martinez ◽

Snehasish Panigrahy ◽

Ajoy Ramalingam ◽

...

Keyword(s):

Simulation Study ◽

Ignition Delay ◽

Delay Time ◽

Ignition Delay Time ◽

Wide Range ◽

C2 Hydrocarbons

Download Full-text

Experimental and Kinetic Modeling of Kerosene-Type Fuels at Gas Turbine Operating Conditions

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.2436575 ◽

2006 ◽

Vol 129 (3) ◽

pp. 655-663 ◽

Cited By ~ 32

Author(s):

P. Gokulakrishnan ◽

G. Gaines ◽

J. Currano ◽

M. S. Klassen ◽

R. J. Roby

Keyword(s):

Low Temperature ◽

Gas Turbine ◽

Ignition Delay ◽

Delay Time ◽

Equivalence Ratio ◽

Ignition Delay Time ◽

Flow Reactor ◽

Fuel Oil ◽

Stirred Reactor ◽

Lean Conditions

Experimental and kinetic modeling of kerosene-type fuels is reported in the present work with special emphasis on the low-temperature oxidation phenomenon relevant to gas turbine premixing conditions. Experiments were performed in an atmospheric pressure, tubular flow reactor to measure ignition delay time of kerosene (fuel–oil No. 1) in order to study the premature autoignition of liquid fuels at gas turbine premixing conditions. The experimental results indicate that the ignition delay time decreases exponentially with the equivalence ratio at fuel-lean conditions. However, for very high equivalence ratios (>2), the ignition delay time approaches an asymptotic value. Equivalence ratio fluctuations in the premixer can create conditions conducive for autoignition of fuel in the premixer, as the gas turbines generally operate under lean conditions during premixed prevaporized combustion. Ignition delay time measurements of stoichiometric fuel–oil No. 1∕air mixture at 1 atm were comparable with that of kerosene type Jet-A fuel available in the literature. A detailed kerosene mechanism with approximately 1400 reactions of 550 species is developed using a surrogate mixture of n-decane, n-propylcyclohexane, n-propylbenzene, and decene to represent the major chemical constituents of kerosene, namely n-alkanes, cyclo-alkanes, aromatics, and olefins, respectively. As the major portion of kerosene-type fuels consists of alkanes, which are relatively more reactive at low temperatures, a detailed kinetic mechanism is developed for n-decane oxidation including low temperature reaction kinetics. With the objective of achieving a more comprehensive kinetic model for n-decane, the mechanism is validated against target data for a wide range of experimental conditions available in the literature. The data include shock tube ignition delay time measurements, jet-stirred reactor reactivity profiles, and plug-flow reactor species time–history profiles. The kerosene model predictions agree fairly well with the ignition delay time measurements obtained in the present work as well as the data available in the literature for Jet A. The kerosene model was able to reproduce the low-temperature preignition reactivity profile of JP-8 obtained in a flow reactor at 12 atm. Also, the kerosene mechanism predicts the species reactivity profiles of Jet A-1 obtained in a jet-stirred reactor fairly well.

Download Full-text

Ignition and Oxidation of 50/50 Butane Isomer Blends

Volume 2: Combustion, Fuels and Emissions ◽

10.1115/gt2009-59673 ◽

2009 ◽

Author(s):

Nicole Donato ◽

Christopher Aul ◽

Eric Petersen ◽

Christopher Zinner ◽

Henry Curran ◽

...

Keyword(s):

Shock Tube ◽

Ignition Delay ◽

Delay Time ◽

Ignition Delay Time ◽

Ignition Time ◽

Pressure Rise ◽

Time Data ◽

Kinetics Modeling ◽

Time Sensitivity ◽

Wide Range

One of the alkanes found within gaseous fuel blends of interest to gas turbine applications is butane. There are two structural isomers of butane, normal butane and iso-butane, and the combustion characteristics of either isomer are not well known. Of particular interest to this work are mixtures of n-butane and iso-butane. A shock-tube experiment was performed to produce important ignition delay time data for these binary butane isomer mixtures which are not currently well studied, with emphasis on 50–50 blends of the two isomers. These data represent the most extensive shock-tube results to date for mixtures of n-butane and iso-butane. Ignition within the shock tube was determined from the sharp pressure rise measured at the endwall which is characteristic of such exothermic reactions. Both experimental and kinetics modeling results are presented for a wide range of stoichiometry (φ = 0.3–2.0), temperature (1056–1598 K), and pressure (1–21 atm). The results of this work serve as validation for the current chemical kinetics model. Correlations in the form of Arrhenius-type expressions are presented which agree well with both the experimental results and the kinetics modeling. The results of an ignition-delay-time sensitivity analysis are provided, and key reactions are identified. The data from this study are compared with the modeling results of 100% normal butane and 100% iso-butane. The 50/50 mixture of n-butane and iso-butane was shown to be more readily ignitable than 100% iso-butane but reacts slower than 100% n-butane only for the richer mixtures. There was little difference in ignition time between the lean mixtures.

Download Full-text

An experimental and kinetic modeling study of the ignition delay characteristics of binary blends of ethane/propane and ethylene/propane in multiple shock tubes and rapid compression machines over a wide range of temperature, pressure, equivalence ratio, and dilution

Combustion and Flame ◽

10.1016/j.combustflame.2021.02.009 ◽

2021 ◽

Vol 228 ◽

pp. 401-414

Author(s):

Sergio Martinez ◽

Mohammadreza Baigmohammadi ◽

Vaibhav Patel ◽

Snehasish Panigrahy ◽

Amrit B. Sahu ◽

...

Keyword(s):

Kinetic Modeling ◽

Ignition Delay ◽

Equivalence Ratio ◽

Shock Tubes ◽

Binary Blends ◽

Wide Range ◽

Rapid Compression ◽

Multiple Shock ◽

Modeling Study

Download Full-text

Reduced Kinetic Mechanism for Reactive Flow Simulation of Syngas/Methane Combustion at Gas Turbine Conditions

Volume 1: Combustion and Fuels, Education ◽

10.1115/gt2006-90573 ◽

2006 ◽

Cited By ~ 7

Author(s):

P. Gokulakrishnan ◽

S. Kwon ◽

A. J. Hamer ◽

M. S. Klassen ◽

R. J. Roby

Keyword(s):

Ignition Delay ◽

Delay Time ◽

Ignition Delay Time ◽

Kinetic Mechanism ◽

Operating Conditions ◽

Reactive Flow ◽

Reduced Mechanism ◽

Wide Range ◽

Model Predictions ◽

Reduced Kinetic Mechanism

The reduced kinetic mechanism for syngas/methane developed in the present work consists of a global reaction step for fuel decomposition in which the fuel molecule breaks down into CH2O and H2. A detailed CH2O/H2/O2 elementary reaction sub-set is included as the formation of intermediate combustion radicals such as OH, H, O, HO2, and H2O2 is essential for accurate predictions of non-equilibrium phenomena such as ignition and extinction. Since the chemical kinetics of H2 and CH2O are the fundamental building blocks of any hydrocarbon oxidation, the inclusion of detailed kinetic mechanisms for CH2O and H2 oxidation enables the reduced mechanism to predict over a wide range of operating conditions provided the reaction rate parameters of fuel-decomposition reaction is optimized over those conditions. Therefore, the rate coefficients for the fuel-decomposition step are estimated and optimized for the ignition delay time measurements of CH4, H2, CH4/H2, CH4/CO and CO/H2 mixtures available in the literature over a wide range of pressures, temperatures and equivalence ratios that are relevant to gas turbine operating conditions. The optimized reduced mechanism, consisting of 15 species and around 40 reactions, is able to predict the ignition delay time and laminar flame speed measurements of CH4, H2, CH4/H2, CH4/CO and CO/H2 mixtures fairly well over a wide range conditions. The model predictions are also compared with that of GRI3.0 mechanism. The reduced kinetic mechanism predicts the ignition delay time of CH4 and CH4/H2 mixtures far better than GRI mechanism at higher pressures. To demonstrate the predictive capability of the model in reactive flow systems, the reduced mechanism was implemented in Star-CD/KINetics commercial code using a RANS turbulence model to simulate CH4/air premixed combustion in a backward facing step. The CFD model predictions of the stable species in the exhaust gas agree well with the GRI mechanism predictions in a chemical reactor network modeling by approximating the backward facing step with a series of perfectly-stirred reactor and plug-flow reactor.

Download Full-text

Investigation on the Ignition Conditions From a Comparison Between Reacting and Non-Reacting Diesel Spray Experiments

Design, Operation, and Application of Modern Internal Combustion Engines and Associated Systems ◽

10.1115/ices2002-456 ◽

2002 ◽

Author(s):

T. Kim ◽

J. B. Ghandhi

Keyword(s):

Ignition Delay ◽

Delay Time ◽

High Speed ◽

Equivalence Ratio ◽

Ignition Delay Time ◽

Ignition Time ◽

Liquid Core ◽

Injection Pressure ◽

Lift Off ◽

Injection Pressures

Natural luminosity images from reacting diesel sprays were acquired in a combustion-type constant-volume spray chamber. Using an ambient condition of 15 kg/m3 and 1000 K, the effects of peak injection pressures (60, 90 and 150 MPa) and nozzle hole sizes (140, 158 and 200 μm) were investigated. From high-speed natural luminosity cinematography, macroscopic reacting spray characteristics such as flame lift-off height and ignition delay time were obtained. For increasing injection pressures the ignition delay time decreased, and the flame lift off height increased. For increasing hole diameter the ignition time delay decreased, and the flame lift-off height decreased. The authors’ previous results of the fuel concentration measurement from non-reacting spray experiments were used to ascertain the local equivalence ratio for the reacting spray during the ignition and initial flame development period. The first detection of the luminosity (believed to be chemiluminescence) signal was found to occur in fuel-rich vapor regions near the boundary of the liquid core with an equivalence ratio near 2 and a temperature of approximately 800 K. These conditions were found to be independent of injection pressure and nozzle diameter for the condition tested (15 kg/m3 and 1000 K ambient), suggesting that this is a kinetically controlled process.

Download Full-text