An experimental and reduced modeling study of the laminar flame speed of jet fuel surrogate components

Fuel ◽  
2013 ◽  
Vol 113 ◽  
pp. 586-597 ◽  
Author(s):  
J.D. Munzar ◽  
B. Akih-Kumgeh ◽  
B.M. Denman ◽  
A. Zia ◽  
J.M. Bergthorson
Keyword(s):  
Laminar Flame ◽  
Jet Fuel ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Reduced Modeling ◽  
Fuel Surrogate ◽  
Modeling Study

An Experimental and Numerical Study of the Laminar Flame Speed of Jet Fuel Surrogate Blends

2012 ◽  
Author(s):  
Bradley M. Denman ◽  
Jeffrey D. Munzar ◽  
Jeffrey M. Bergthorson
Keyword(s):  
Numerical Simulations ◽  
Laminar Flame ◽  
Velocity Profiles ◽  
Jet Fuel ◽  
Flame Speed ◽  
Aviation Fuel ◽  
Laminar Flame Speed ◽  
Measured Velocity ◽  
Combustion Properties ◽  
Fuel Surrogate

Kerosene-type fuels are the most common aviation fuel, and an understanding of their combustion properties is essential for achieving optimized gas turbine operation. Presently, however, there is lack of experimental flame speed data available by which to validate the chemical kinetic mechanisms necessary for effective computational studies. In this study, premixed jet fuel surrogate blends and commercial kerosene are studied using particle image velocimetry in a stagnation flame geometry. Numerical simulations of each experiment are obtained using the CHEMKIN-PRO software package and the JetSurF 2.0 mechanism. The neat hydrocarbon surrogates investigated include n-decane, methylcyclohexane, and toluene, which represent the alkane, cycloalkane, and aromatic components of conventional aviation fuel, respectively. Two blends are studied in this paper. The first is a binary blend formulated to reproduce the laminar flame speed of aviation fuel using a mixing rule based on the laminar flame speed and adiabatic flame temperature of the hydrocarbon components, weighted by their respective mixture mole fractions. The second blend is a tertiary blend formulated to emulate the hydrogen to carbon ratio of the kerosene studied. All of the considered fuels and blends are studied at three equivalence ratios, corresponding to lean, stoichiometric, and rich conditions, and at several stretch rates. The centreline axial velocity profiles from numerical simulations are directly compared to the measured velocity profiles to validate the mechanism at each condition. The difference between the experimental and simulated reference flame speed is used to infer the true unstretched laminar flame speed of the mixture. These results allow the effectiveness of the different blending methodologies to be assessed.

scholarly journals The Influence of Diluent Gases on Combustion Properties of Natural Gas: A Combined Experimental and Modeling Study

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Sandra Richter ◽  
Jörn Ermel ◽  
Thomas Kick ◽  
Marina Braun-Unkhoff ◽  
Clemens Naumann ◽  
...  
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Laminar Flame ◽  
Ambient Pressure ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Diverse Range ◽  
Combustion Properties ◽  
Modeling Study ◽  
A Share

Currently, new concepts for power generation are discussed, as a response to combat global warming due to CO2 emissions stemming from the combustion of fossil fuels. These concepts include new, low-carbon fuels as well as centralized and decentralized solutions. Thus, a more diverse range of fuel supplies will be used, with (biogenic) low-caloric gases such as syngas and coke oven gas (COG) among them. Typical for theses low-caloric gases is the amount of hydrogen, with a share of 50% and even higher. However, hydrogen mixtures have a higher reactivity than natural gas (NG) mixtures, burned mostly in today's gas turbine combustors. Therefore, in the present work, a combined experimental and modeling study of nitrogen-enriched hydrogen–air mixtures, some of them with a share of methane, to be representative for COG, will be discussed focusing on laminar flame speed data as one of the major combustion properties. Measurements were performed in a burner test rig at ambient pressure and at a preheat temperature T0 of 373 K. Flames were stabilized at fuel–air ratios between about φ = 0.5–2.0 depending on the specific fuel–air mixture. This database was used for the validation of four chemical kinetic reaction models, including an in-house one, and by referring to hydrogen-enriched NG mixtures. The measured laminar flame speed data of nitrogen-enriched methane–hydrogen–air mixtures are much smaller than the ones of nitrogen-enriched hydrogen–air mixtures. The grade of agreement between measured and predicted data depends on the type of flames and the type of reaction model as well as of the fuel–air ratio: a good agreement was found in the fuel lean and slightly fuel-rich regime; a large underprediction of the measured data exists at very fuel-rich ratios (φ > 1.4). From the results of the present work, it is obvious that further investigations should focus on highly nitrogen-enriched methane–air mixtures, in particular for very high fuel–air ratio (φ > 1.4). This knowledge will contribute to a more efficient and a more reliable use of low-caloric gases for power generation.

Comparison of Laminar Flame Speeds, Extinction Stretch Rates and Vapor Pressures of Jet A-1/HRJ Biojet Fuel Blends

2014 ◽  
Author(s):  
Jeffrey D. Munzar ◽  
Ahmed Zia ◽  
Philippe Versailles ◽  
Rodrigo Jiménez ◽  
Jeffrey M. Bergthorson ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Laminar Flame ◽  
Alternative Fuel ◽  
Jet Fuel ◽  
Flame Speed ◽  
Aviation Industry ◽  
Laminar Flame Speed ◽  
Vapor Pressures ◽  
Fuel Blends ◽  
Combustion Properties

An emerging goal within the aviation industry is to replace conventional jet fuel with biologically-derived alternative fuel sources. However, the combustion properties of these potential fuels must be thoroughly characterized before they can be considered as replacements in turbomachinery applications. In this study, seven candidate alternative fuel blends, derived from two biological feedstocks and blended in different quantities with Jet A-1, are considered. For each blend, the laminar flame speed, non-premixed extinction stretch rate, and vapor pressure are experimentally determined and compared to numerical simulations and to Jet A-1 data. Hydrodynamically-stretched flame speeds are determined by applying particle image velocimetry (PIV) to an atmospheric pressure, preheated jet-wall stagnation flame, and the unstretched laminar flame speed is inferred using a direct comparison method in conjunction with a binary jet-fuel surrogate, with results spanning a wide equivalence ratio range. Extinction stretch rates were measured using particle tracking velocimetry (PTV) in a non-premixed counterflow diffusion flame, over a range of fuel mass fractions diluted in nitrogen carrier gas. Finally, the vapor pressure of the seven biojet/Jet A-1 fuel blends was measured using an isoteniscope over a wide temperature range. The results of this study indicate that moderate blends of hydrotreated renewable jet (HRJ) fuel with Jet A-1 have similar combustion properties to conventional jet fuel, highlighting their suitability as drop-in replacements, while higher blend levels of HRJ fuel, regardless of the crop source, lead to definitive changes in the combustion parameters investigated here.

A Method for Determining the Laminar Flame Speed of Jet Fuels Using Combustion Bomb Pressure

2012 ◽  
Author(s):  
Andy Yates ◽  
Victor Burger ◽  
Carl Viljoen
Keyword(s):  
Laminar Flame ◽  
Jet Fuel ◽  
Synthetic Jet ◽  
Flame Speed ◽  
Optical Measurements ◽  
Jet Fuels ◽  
Relevant Parameter ◽  
Laminar Flame Speed ◽  
Combustion Pressure ◽  
Pressure Trace

This paper describes the use of a spherical combustion bomb to determine the laminar flame speed and Markstein length of a selection of hydrocarbon fuels. The fuels nominally represented Jet A-1 but some were doped with various component compounds which were chosen so as to vary particular jet fuel specification in relative isolation. Analyses of this kind are typically based on optical measurements and, to simplify the analysis, an approximation of constant pressure is usually achieved by limiting the useable data to the early stages of flame propagation only. The analysis methodology presented in this paper differs inasmuch that calculations were based solely on the recorded pressure data. Moreover, by deducing the response of the flame speed to pressure and temperature, it was possible to utilize the whole combustion pressure record which significantly increased the volume of useful data that could be obtained from each experiment. Other practical difficulties that are often encountered such as flame winkling at large diameters, especially with rich mixtures, were minimized by using a small bomb of only 100mm diameter. The method of analysis via the pressure trace rendered any flame winkling easily discernable wherefrom it could be easily eliminated. For each fuel, at least six repeat combustion pressure records (about 90 data points each) were obtained for each of six different air-fuel ratios spanning the range from lean to rich and the whole sequence was repeated at a higher initial temperature. This provided a database of over 6000 individual calculations of laminar flame speed from which the relevant parameter coefficients were obtained by means of a regression technique. It was found that the effects of changing the blend composition could be discerned in the various laminar flame speed results and that significant variation in laminar flame speed could possibly be “tailored” into a synthetic jet fuel formulation.

scholarly journals Experimental and Kinetic Modeling Study of Laminar Flame Speed of Dimethoxymethane and Ammonia Blends

2020 ◽  
Vol 34 (11) ◽  
pp. 14726-14740
Author(s):  
Ayman M. Elbaz ◽  
Binod Raj Giri ◽  
Gani Issayev ◽  
Krishna P. Shrestha ◽  
Fabian Mauss ◽  
...  
Keyword(s):  
Kinetic Modeling ◽  
Laminar Flame ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Modeling Study

Experimental and modeling study of laminar flame speed and non-premixed counterflow ignition of n-heptane

2009 ◽  
Vol 32 (1) ◽  
pp. 1245-1252 ◽  
Author(s):  
A.J. Smallbone ◽  
W. Liu ◽  
C.K. Law ◽  
X.Q. You ◽  
H. Wang
Keyword(s):  
Laminar Flame ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Modeling Study

The Influence of Diluent Gases on Combustion Properties of Natural Gas: A Combined Experimental and Modeling Study

2015 ◽  
Author(s):  
Jörn Ermel ◽  
Sandra Richter ◽  
Thomas Kick ◽  
Marina Braun-Unkhoff ◽  
Clemens Naumann ◽  
...  
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Laminar Flame ◽  
Ambient Pressure ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
Diverse Range ◽  
Combustion Properties ◽  
Modeling Study ◽  
A Share

Currently, new concepts for power generation are discussed, as a response to combat global warming due to CO2 emissions stemming from the combustion of fossil fuels. These concepts include new, low-carbon fuels as well as centralized and decentralized solutions. Thus, a more diverse range of fuel supplies will be used, with (biogenic) low-caloric gases such as syngas and coke oven gas (COG) among them. Typical for theses low-caloric gases is the amount of hydrogen, with a share of 50% and even higher. However, hydrogen mixtures have a higher reactivity than natural gas (NG) mixtures, burned mostly in today’s gas turbine combustors. Therefore, in the present work, a combined experimental and modeling study of nitrogen-enriched hydrogen-air mixtures, some of them with a share of methane, to be representative for COG, will be discussed focusing on laminar flame speed data Su as one of the major combustion properties. Measurements were performed in a burner test rig at ambient pressure and at a preheat temperature T0 of 373 K. Flames were stabilized at fuel-air ratios between about φ = 0.5–2.1, depending on the specific fuel-air mixture. This database was used for the validation of four chemical kinetic reaction models, including an in-house one, and by referring to hydrogen-enriched natural gas mixtures. The measured laminar flame speed data of nitrogen-enriched methane-hydrogen-air mixtures are much smaller than the ones of nitrogen-enriched hydrogen-air mixtures. The grade of agreement between measured and predicted data depends on the type of flames and the type of reaction model as well as of the fuel-air ratio: good agreement was found in the fuel lean and slightly fuel rich regime; a large underprediction of the measured data exists at very fuel-rich ratios (φ > 1.4). From the results of the present work, it is obvious that further investigations should focus on highly nitrogen-enriched methane-air mixtures, in particular for very high fuel-air ratio (φ > 1.4). This knowledge will contribute to a more efficient and a more reliable use of low-caloric gases for power generation.

A Numerical Study on the Reactivity of Biogas/Reformed-Gas/Air and Methane/Reformed-Gas/Air Mixtures at Gas Turbine Relevant Conditions

2016 ◽  
Author(s):  
Pablo Diaz Gomez Maqueo ◽  
Philippe Versailles ◽  
Gilles Bourque ◽  
Jeffrey M. Bergthorson
Keyword(s):  
Gas Turbine ◽  
Laminar Flame ◽  
Numerical Study ◽  
Flame Temperature ◽  
Flame Speed ◽  
Flame Stability ◽  
Laminar Flame Speed ◽  
Fuel Reforming ◽  
Numerical Work ◽  
Chemical Effects

This study investigates the increase in methane and biogas flame reactivity enabled by the addition of syngas produced through fuel reforming. To isolate thermodynamic and chemical effects on the reactivity of the mixture, the burner simulations are performed with a constant adiabatic flame temperature of 1800 K. Compositions and temperatures are calculated with the chemical equilibrium solver of CANTERA® and the reactivity of the mixture is quantified using the adiabatic, freely-propagating premixed flame, and perfectly-stirred reactors of the CHEMKIN-Pro® software package. The results show that the produced syngas has a content of up to 30 % H2 with a temperature up to 950 K. When added to the fuel, it increases the laminar flame speed while maintaining a burning temperature of 1800 K. Even when cooled to 300 K, the laminar flame speed increases up to 30 % from the baseline of pure biogas. Hence, a system can be developed that controls and improves biogas flame stability under low reactivity conditions by varying the fraction of added syngas to the mixture. This motivates future experimental work on reforming technologies coupled with gas turbine exhausts to validate this numerical work.

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