Laminar Flame Speeds of C5 to C8 n-Alkanes at Elevated Pressures and Temperatures

2010 ◽  
Author(s):  
Andrew Kelley ◽  
Andrew Smallbone ◽  
Delin Zhu ◽  
Chung Law
Keyword(s):  
Laminar Flame ◽  
Elevated Pressures

The Structure of Laminar Premixed H2-Air Flames at Elevated Pressures

2000 ◽  
Vol 214 (4) ◽  
Author(s):  
M. El-Gamal ◽  
E. Gutheil ◽  
J. Warnatz
Keyword(s):  
Laminar Flame ◽  
Flame Structure ◽  
Ideal Gas ◽  
Fortran Program ◽  
Laminar Flame Speed ◽  
Real Gas ◽  
One Dimensional ◽  
Rocket Propulsion ◽  
Elevated Pressures ◽  
Engine Combustion

In high-pressure flames that occur in many practical combustion devices such as industrial furnaces, rocket propulsion and internal engine combustion, the assumption of an ideal gas is not appropriate. The present paper presents a model that includes modifications of the equation of state, transport and thermodynamic properties. The model is implemented into a Fortran program that was developed to simulate numerically one-dimensional planar premixed flames. The influence of the modifications for the real gas behavior on the laminar flame speed and on flame structure is illustrated for stoichiometric H

A comparison study of cyclopentane and cyclohexane laminar flame speeds at elevated pressures and temperatures

Fuel ◽  
2018 ◽  
Vol 234 ◽  
pp. 238-246 ◽  
Author(s):  
Haoran Zhao ◽  
Jinhua Wang ◽  
Xiao Cai ◽  
Zemin Tian ◽  
Qianqian Li ◽  
...  
Keyword(s):  
Laminar Flame ◽  
Comparison Study ◽  
Elevated Pressures

Laminar Flame Speed Measurements and Modeling of Pure Alkanes and Alkane Blends at Elevated Pressures

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
William Lowry ◽  
Jaap de Vries ◽  
Michael Krejci ◽  
Eric Petersen ◽  
Zeynep Serinyel ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbines ◽  
Laminar Flame ◽  
Flame Speed ◽  
Published Data ◽  
Laminar Flame Speed ◽  
Binary Blends ◽  
Elevated Pressures ◽  
True Value

Alkanes such as methane, ethane, and propane make up a large portion of most natural gas fuels. Natural gas is the primary fuel used in industrial gas turbines for power generation. Because of this, a fundamental understanding of the physical characteristics such as the laminar flame speed is necessary. Most importantly, this information is needed at elevated pressures to have the most relevance to the gas turbine industry for engine design. This study includes experiments performed at elevated pressures, up to 10 atm initial pressure, and investigates the fuels in a pure form as well as in binary blends. Flame speed modeling was done using an improved version of the kinetics model that the authors have been developing over the past few years. Modeling was performed for a wide range of conditions, including elevated pressures. Experimental conditions include pure methane, pure ethane, 80/20 mixtures of methane/ethane, and 60/40 mixtures of methane/ethane at initial pressures of 1 atm, 5 atm, and 10 atm. Also included in this study are pure propane and 80/20 methane/propane mixtures at 1 atm and 5 atm. The laminar flame speed and Markstein length measurements were obtained from a high-pressure flame speed facility using a constant-volume vessel. The facility includes optical access, a high-speed camera, a schlieren optical setup, a mixing manifold, and an isolated control room. The experiments were performed at room temperature, and the resulting images were analyzed using linear regression. The experimental and modeling results are presented and compared with previously published data. The data herein agree well with the published data. In addition, a hybrid correlation was created to perform a rigorous uncertainty analysis. This correlation gives the total uncertainty of the experiment with respect to the true value rather than reporting the standard deviation of a repeated experiment. Included in the data set are high-pressure results at conditions where in many cases for the single-component fuels few data existed and for the binary blends no data existed prior to this study. Overall, the agreement between the model and data is excellent.

Laminar Flame Speed and Ignition Delay Time Data for the Kinetic Modeling of Hydrogen and Syngas Fuel Blends

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Michael C. Krejci ◽  
Olivier Mathieu ◽  
Andrew J. Vissotski ◽  
Sankaranarayanan Ravi ◽  
Travis G. Sikes ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Chemical Kinetics ◽  
Ignition Delay ◽  
Laminar Flame ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Elevated Pressures ◽  
Ignition Delay Times ◽  
Wide Range ◽  
Delay Times

Laminar flame speeds and ignition delay times have been measured for hydrogen and various compositions of H2/CO (syngas) at elevated pressures and elevated temperatures. Two constant-volume cylindrical vessels were used to visualize the spherical growth of the flame through the use of a schlieren optical setup to measure the laminar flame speed of the mixture. Hydrogen experiments were performed at initial pressures up to 10 atm and initial temperatures up to 443 K. A syngas composition of 50/50 by volume was chosen to demonstrate the effect of carbon monoxide on H2-O2 chemical kinetics at standard temperature and pressures up to 10 atm. All atmospheric mixtures were diluted with standard air, while all elevated-pressure experiments were diluted with a He:O2 ratio of 7:1 to minimize instabilities. The laminar flame speed measurements of hydrogen and syngas are compared to available literature data over a wide range of equivalence ratios, where good agreement can be seen with several data sets. Additionally, an improved chemical kinetics model is shown for all conditions within the current study. The model and the data presented herein agree well, which demonstrates the continual, improved accuracy of the chemical kinetics model. A high-pressure shock tube was used to measure ignition delay times for several baseline compositions of syngas at three pressures across a wide range of temperatures. The compositions of syngas (H2/CO) by volume presented in this study included 80/20, 50/50, 40/60, 20/80, and 10/90, all of which are compared to previously published ignition delay times from a hydrogen-oxygen mixture to demonstrate the effect of carbon monoxide addition. Generally, an increase in carbon monoxide increases the ignition delay time, but there does seem to be a pressure dependency. At low temperatures and pressures higher than about 12 atm, the ignition delay times appear to be indistinguishable with an increase in carbon monoxide. However, at high temperatures the relative composition of H2 and CO has a strong influence on ignition delay times. Model agreement is good across the range of the study, particularly at the elevated pressures.

Laminar flame speeds of cyclohexane and mono-alkylated cyclohexanes at elevated pressures

2012 ◽  
Vol 159 (4) ◽  
pp. 1417-1425 ◽  
Author(s):  
Fujia Wu ◽  
Andrew P. Kelley ◽  
Chung K. Law
Keyword(s):  
Laminar Flame ◽  
Elevated Pressures

On transition to cellularity in expanding spherical flames

2007 ◽  
Vol 583 ◽  
pp. 1-26 ◽  
Author(s):  
G. JOMAAS ◽  
C. K. LAW ◽  
J. K. BECHTOLD
Keyword(s):  
High Speed ◽  
Laminar Flame ◽  
Flame Structure ◽  
Lewis Number ◽  
Quantitative Agreement ◽  
Previous Theory ◽  
Detailed Chemistry ◽  
Flame Thickness ◽  
Elevated Pressures ◽  
Spherical Flames

The instant of transition to cellularity of centrally ignited, outwardly propagating spherical flames in a reactive environment of fuelx–oxidizer mixture, at atmospheric and elevated pressures, was experimentally determined using high-speed schlieren imaging and subsequently interpreted on the basis of hydrodynamic and diffusional–thermal instabilities. Experimental results show that the transition Péclet number, Pec = RcℓL, assumes an almost constant value for the near-equidiffusive acetylene flames with wide ranges in the mixture stoichiometry, oxygen concentration and pressure, where Rc is the flame radius at transition and ℓL the laminar flame thickness. However, for the non-equidiffusive hydrogen and propane flames, Pec respectively increases and decreases somewhat linearly with the mixture equivalence ratio. Evaluation of Pec using previous theory shows complete qualitative agreement and satisfactory quantitative agreement, demonstrating the insensitivity of Pec to all system parameters for equidiffusive mixtures, and the dominance of the Markstein number, Ze(Le – 1), in destabilization for non-equidiffusive mixtures, where Ze is the Zel'dovich number and Le the Lewis number. The importance of using locally evaluated values of ℓL, Ze and Le, extracted from either computationally simulated one-dimensional flame structure with detailed chemistry and transport, or experimentally determined response of stretched flames, in the evaluation of Pec is emphasized.

scholarly journals Flame front/turbulence interaction for syngas fuels in the thin reaction zones regime: turbulent and stretched laminar flame speeds at elevated pressures and temperatures

2013 ◽  
Vol 724 ◽  
pp. 36-68 ◽  
Author(s):  
S. Daniele ◽  
J. Mantzaras ◽  
P. Jansohn ◽  
A. Denisov ◽  
K. Boulouchos
Keyword(s):  
Flame Front ◽  
Laminar Flame ◽  
Strong Dependence ◽  
Turbulent Flame ◽  
Pure Hydrogen ◽  
Elevated Pressures ◽  
Image Velocimetry ◽  
Planar Laser ◽  
Reaction Zones ◽  
Reactive Mixture

AbstractExperiments were performed in dump-stabilized axisymmetric flames to assess turbulent flame speeds (${S}_{T} $) and mean flamelets speeds (stretched laminar flame speeds, ${S}_{L, k} $). Fuels with significantly different thermodiffusive properties have been investigated, ranging from pure methane to syngas (${\mathrm{H} }_{2} \text{{\ndash}} \mathrm{CO} $ blends) and pure hydrogen, while the pressure was varied from 0.1 to 1.25 MPa. Flame front corrugation was measured with planar laser-induced fluorescence (PLIF) of the OH radical, while turbulence quantities were determined with particle image velocimetry (PIV). Two different analyses based on mass balance were performed on the acquired flame images. The first method assessed absolute values of turbulent flame speeds and the second method, by means of an improved fractal methodology, provided normalized turbulent flame speeds (${S}_{T} / {S}_{L, k} $). Deduced average Markstein numbers exhibited a strong dependence on pressure and hydrogen content of the reactive mixture. It was shown that preferential-diffusive-thermal (PDT) effects acted primarily on enhancing the stretched laminar flame speeds rather than on increasing the flame front corrugations. Interaction between flame front and turbulent eddies measured by the fractal dimension was shown to correlate with the eddy temporal activity.

Revisit laminar premixed ethylene flames at elevated pressures: A mass spectrometric and laminar flame propagation study

2021 ◽  
Vol 230 ◽  
pp. 111422
Author(s):  
Siyuan Ma ◽  
Xiaoyuan Zhang ◽  
Artёm Dmitriev ◽  
Andrey Shmakov ◽  
Oleg Korobeinichev ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Laminar Flame ◽  
Mass Spectrometric ◽  
Elevated Pressures ◽  
Ethylene Flames

Laminar flame speeds of H 2 /CO with CO 2 dilution at normal and elevated pressures and temperatures

Fuel ◽  
2015 ◽  
Vol 148 ◽  
pp. 32-38 ◽  
Author(s):  
Minchao Han ◽  
Yuhua Ai ◽  
Zheng Chen ◽  
Wenjun Kong
Keyword(s):  
Laminar Flame ◽  
Elevated Pressures
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