Ignition Delay Time and Laminar Flame Velocity for a Combined Laser–Microwave Ignition

2011 ◽  
Vol 39 (12) ◽  
pp. 3263-3268 ◽  
Author(s):  
Albina A. Tropina ◽  
James B. Michael ◽  
Mikhail N. Shneider ◽  
Richard B. Miles
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Flame Velocity ◽  
Microwave Ignition

The Influence of Singlet Oxygen and Ozone on the Combustion in Methane-Air Mixture

2013 ◽  
Vol 699 ◽  
pp. 111-118
Author(s):  
Rui Shi ◽  
Chang Hui Wang ◽  
Yan Nan Chang
Keyword(s):  
Singlet Oxygen ◽  
Chemical Kinetics ◽  
Mole Fraction ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Combustion Products ◽  
Flame Speed ◽  
Air Mixing

Based on GRI3.0, we study the main chemical kinetics process about reactions of singlet oxygen O2(a1Δg) and ozone O3 with methane-air combustion products, inherit and further develop research in chemical kinetics process with enhancement effects on methane-air mixed combustion by these two molecules. In addition, influence of these two molecules on ignition delay time and flame speed of laminar mixture are considered in our numerical simulation research. This study validates the calculation of this model which cotains these two active molecules by using experimental data of ignition delay time and the speed of laminar flame propagation. In CH4-air mixing laminar combustion under fuel-lean condition(ф=0.5), flame speed will be increased, and singlet oxygen with 10% of mole fraction increases it by 80.34%, while ozone with 10% mole fraction increase it by 127.96%. It mainly because active atoms and groups(O, H, OH, CH3, CH2O, CH3O, etc) will be increased a lot after adding active molecules in the initial stage, and chain reaction be reacted greatly, inducing shortening of reaction time and accelerating of flame speed. Under fuel rich(ф=1.5), accelerating of flame speed will be weakened slightly, singlet oxygen with 10% in molecular oxygen increase it by 48.93%, while ozone with 10% increase it by 70.25%.

Numerical Study on the Effect of Real Syngas Compositions on Ignition Delay Times and Laminar Flame Speeds at Gas Turbine Conditions

2013 ◽  
Author(s):  
Olivier Mathieu ◽  
Eric L. Petersen ◽  
Alexander Heufer ◽  
Nicola Donohoe ◽  
Wayne Metcalfe ◽  
...  
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Gas Turbines ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Numerical Study ◽  
Fuel Mixture ◽  
Flame Speed ◽  
Operating Conditions ◽  
Combustion Properties

Depending on the feedstock and the production method, the composition of syngas can include (in addition to H2 and CO) small hydrocarbons, diluents (CO2, water, and N2), and impurities (H2S, NH3, NOx, etc.). Despite this fact, most of the studies on syngas combustion do not include hydrocarbons or impurities and in some cases not even diluents in the fuel mixture composition. Hence, studies with realistic syngas composition are necessary to help designing gas turbines. The aim of this work was to investigate numerically the effect of the variation in the syngas composition on some fundamental combustion properties of premixed systems such as laminar flame speed and ignition delay time at realistic engine operating conditions. Several pressures, temperatures, and equivalence ratios were investigated. To perform this parametric study, a state-of-the-art C0-C5 detailed kinetics mechanism was used. Results of this study showed that the addition of hydrocarbons generally reduces the reactivity of the mixture (longer ignition delay time, slower flame speed) due to chemical kinetic effects. The amplitude of this effect is however dependent on the nature and concentration of the hydrocarbon as well as the initial condition (pressure, temperature, and equivalence ratio).

Chemical Kinetic Model Reduction and Analysis of Tetrahydrofuran Combustion Using Stochastic Species Elimination

2020 ◽  
Author(s):  
Mazen A. Eldeeb ◽  
Malshana Wadugurunnehalage
Keyword(s):  
Kinetic Model ◽  
Model Reduction ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Chemical Kinetic ◽  
Reduced Model ◽  
Chemical Kinetic Model ◽  
Parameter Modification

Abstract In this work, a chemical kinetic modeling study of the high-temperature ignition and laminar flame behavior of Tetrahydrofuran (THF), a promising second-generation transportation biofuel, is presented. Stochastic Species Elimination (SSE) model reduction approach (Eldeeb and Akih-Kumgeh, Proceedings of ASME Power Conference 2018) is implemented to develop multiple skeletal versions of a detailed chemical kinetic model of THF (Fenard et al., Combustion and Flame, 2018) based on ignition delay time simulations at various pressures and temperature ranges. The detailed THF model contains 467 species and 2390 reactions. The developed skeletal versions are combined into an overall reduced model of THF, consisting of 193 species and 1151 reactions. Ignition delay time simulations are performed using detailed and reduced models, with varying levels of agreement observed at most conditions. Sensitivity analysis is then performed to identify the most important reactions responsible for the observed performance of the reduced model. Reaction rate parameter modification is performed for such reactions in order to improve the agreement of detailed and reduced model predictions with literature experimental ignition data. The work contributes toward improved understanding and modeling of the oxidation kinetics of potential transportation biofuels, especially cyclic ethers.

Ignition delay time and laminar flame speed measurements of mixtures containing diisopropyl-methylphosphonate (DIMP)

2020 ◽  
Vol 215 ◽  
pp. 66-77
Author(s):  
Olivier Mathieu ◽  
Travis Sikes ◽  
Waruna D. Kulatilaka ◽  
Eric L. Petersen
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Flame Speed ◽  
Laminar Flame Speed

Numerical Study on the Effect of Real Syngas Compositions on Ignition Delay Times and Laminar Flame Speeds at Gas Turbine Conditions

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Olivier Mathieu ◽  
Eric L. Petersen ◽  
Alexander Heufer ◽  
Nicola Donohoe ◽  
Wayne Metcalfe ◽  
...  
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Gas Turbines ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Flame Speed ◽  
Operating Conditions ◽  
Laminar Flame Speed ◽  
Ignition Delay Times ◽  
Delay Times

Depending on the feedstock and the production method, the composition of syngas can include (in addition to H2 and CO) small hydrocarbons, diluents (CO2, water, and N2), and impurities (H2S, NH3, NOx, etc.). Despite this fact, most of the studies on syngas combustion do not include hydrocarbons or impurities and in some cases not even diluents in the fuel mixture composition. Hence, studies with realistic syngas composition are necessary to help in designing gas turbines. The aim of this work was to investigate numerically the effect of the variation in the syngas composition on some fundamental combustion properties of premixed systems such as laminar flame speed and ignition delay time at realistic engine operating conditions. Several pressures, temperatures, and equivalence ratios were investigated for the ignition delay times, namely 1, 10, and 35 atm, 900–1400 K, and ϕ = 0.5 and 1.0. For laminar flame speed, temperatures of 300 and 500 K were studied at pressures of 1 atm and 15 atm. Results showed that the addition of hydrocarbons generally reduces the reactivity of the mixture (longer ignition delay time, slower flame speed) due to chemical kinetic effects. The amplitude of this effect is, however, dependent on the nature and concentration of the hydrocarbon as well as the initial condition (pressure, temperature, and equivalence ratio).

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.

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