Understanding the Effect of Oxygenated Biofuels Addition on Combustion Characteristics of Gasoline

2018 ◽  
Author(s):  
Shrabanti Roy ◽  
Saeid Zare ◽  
Omid Askari
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Equivalence Ratio ◽  
Ignition Delay Time ◽  
Combustion Characteristics ◽  
Wide Range ◽  
Oxygenated Fuels ◽  
Laminar Burning Speed

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.

Understanding the Effect of Oxygenated Additives on Combustion Characteristics of Gasoline

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Shrabanti Roy ◽  
Saeid Zare ◽  
Omid Askari
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Combustion Characteristics ◽  
Characteristic Change ◽  
Time Behavior ◽  
Alternative Source ◽  
Oxygenated Additives ◽  
Wide Range ◽  
Laminar Burning Speed

Laminar burning speed and ignition delay time behavior of iso-octane at the presence of two different biofuels, ethanol and 2,5 dimethyl furan (DMF), was studied in this work. Biofuels are considered as a better alternative source of fossil fuels. There is a potentiality that combustion characteristics of iso-octane can be improved using biofuels as an oxygenated additive. In this study, three different blending ratios of 5%, 25%, and 50% of ethanol/iso-octane and DMF/iso-octane were investigated. For laminar burning speed calculation, equivalence ratio of 0.6–1.4 was considered. Ignition delay time was measured under temperature ranges from 650 K to 1100 K. Two different mechanisms were considered in numerical calculation. These mechanisms were validated by comparing the results of pure fuels with wide range of experimental and numerical data. The characteristic change of iso-octane with the presence of additives was observed by comparing the results with pure fuel. Significant change was observed on behavior of iso-octane at 50% blending ratio. A comparison was also done on the effect of two different additives. It has found that addition of DMF brings significant changes on iso-octane characteristics comparing to ethanol.

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

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.

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

2020 ◽  
Vol 34 (3) ◽  
pp. 3755-3771 ◽  
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

scholarly journals Numerical Investigation of Combustion Characteristics of a Wave Rotor Combustor Based on a Reduced Reaction Mechanism of Ethylene

2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
Jianzhong Li ◽  
Li Yuan ◽  
Wei Li ◽  
Kaichen Zhang
Keyword(s):  
Reaction Mechanism ◽  
Flame Propagation ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Wave Rotor ◽  
Elementary Reactions ◽  
Coupling Time

To improve simulations of the flame and pressure wave propagation process and investigate the combustion characteristics of a wave rotor combustor (WRC), direct relation graphs with error propagation (DRGEP), quasi-steady-state assumption (QSSA), and sensitivity analysis were used to establish a reduced reaction mechanism comprised of 23 species and 55 elementary reactions, based on the LLNL N-Butane mechanism. The reduced reaction mechanism of ethylene was combined with an eddy dissipation concept (EDC) model to simulate the flame propagation characteristics in a simplified WRC channel. The effects of spoilers with different blockage ratios and hot-jets of different species on combustion characteristics of flame propagation and pressure rise in the WRC channel were investigated. When the heated inert air was used as hot-jet, the ignition delay time of WRC would increase, which indicated that the activity of the burned gas from the hot-jet igniter would affect the ignition delay time. The spoiler facilitates the coupling of flame and shock waves to reduce the coupling time and distance. With the blockage ratio of the spoiler increasing, the coupling time and distance would be reduced.

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

2006 ◽  
Vol 129 (3) ◽  
pp. 655-663 ◽  
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.

Ignition and Oxidation of 50/50 Butane Isomer Blends

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.

scholarly journals Research on Combustion Characteristics of Air–Light Hydrocarbon Mixing Gas

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 730 ◽  
Author(s):  
Zhiqun Meng ◽  
Jinggang Wang ◽  
Chuchao Xiong ◽  
Jiawen Qi ◽  
Liquan Hou
Keyword(s):  
Residence Time ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Combustion Characteristics ◽  
Light Hydrocarbon ◽  
Laminar Flame Speed ◽  
Emission Index ◽  
Co Emission

Air–light hydrocarbon mixing gas is a new type of city gas which is composed of light hydrocarbon with the main component of n-pentane and air mixed in a certain proportion. To explore the dominant reactions for CO production of air–light hydrocarbon mixing gas with different mixing degrees at the critical equivalence ratios, a computational study was conducted on the combustion characteristics, including the ignition delay time, laminar flame speed, extinction residence time, and emission of air–light hydrocarbon mixing gas at atmospheric pressure and room temperature in the present study. The calculated results indicate that the ignition delay time of air–light hydrocarbon mixing gas at temperatures of 1000–1118 K is greater than that of n-pentane, while the opposite at temperatures of 1118–1600 K. From the study of the laminar flame speed and ignition delay time, it was found that the essence of air–light hydrocarbon mixing gas is that its attribute parameter is determined by the ratio of n-pentane to the total amount of air at the moment of combustion. The changes in the extinction residence time and the CO emission index of air–light hydrocarbon mixing gas are not synchronized, that is the CO emission index is not necessarily small for air–light hydrocarbon mixing gas with excellent extinction residence time. CO sensitivity analysis and CO rate of production identified key species and reactions that are primarily responsible for CO formation and annihilation. The mixing degree plays a key role in the CO emission index of air–light hydrocarbon mixing gas, which has a constructive opinion on the future experiment and application of air–light hydrocarbon mixing gas.

Sign in / Sign up

Export Citation Format

Share Document