Laminar flame speed correlations for pure-hydrogen and high-hydrogen content syngas blends with various diluents

2012 ◽  
Vol 37 (24) ◽  
pp. 19177-19189 ◽  
Author(s):  
Sankaranarayanan Ravi ◽  
Eric L. Petersen
Keyword(s):  
Hydrogen Content ◽  
Laminar Flame ◽  
Flame Speed ◽  
Pure Hydrogen ◽  
Laminar Flame Speed ◽  
High Hydrogen ◽  
High Hydrogen Content

scholarly journals Investigation of Hydrogen Content and Dilution Effect on Syngas/Air Premixed Turbulent Flame Using OH Planar Laser-Induced Fluorescence

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1894
Author(s):  
Li Yang ◽  
Wubin Weng ◽  
Yanqun Zhu ◽  
Yong He ◽  
Zhihua Wang ◽  
...  
Keyword(s):  
Hydrogen Content ◽  
Laminar Flame ◽  
Turbulent Flame ◽  
Laser Induced Fluorescence ◽  
Flame Speed ◽  
Laminar Flame Speed ◽  
High Hydrogen ◽  
Turbulent Flame Speed ◽  
Planar Laser Induced Fluorescence ◽  
Planar Laser

Syngas produced by gasification, which contains a high hydrogen content, has significant potential. The variation in the hydrogen content and dilution combustion are effective means to improve the steady combustion of syngas and reduce NOx emissions. OH planar laser-induced fluorescence technology (OH-PLIF) was applied in the present investigation of the turbulence of a premixed flame of syngas with varied compositions of H2/CO. The flame front structure and turbulent flame velocities of syngas with varied compositions and turbulent intensities were analyzed and calculated. Results showed that the trend in the turbulent flame speed with different hydrogen proportions and dilutions was similar to that of the laminar flame speed of the corresponding syngas. A higher hydrogen proportion induced a higher turbulent flame speed, higher OH concentration, and a smaller flame. Dilution had the opposite effect. Increasing the Reynolds number also increased the turbulent flame speed and OH concentration. In addition, the effect of the turbulence on the combustion of syngas was independent of the composition of syngas after the analysis of the ratio between the turbulent flame speed and the corresponding laminar flame speed, for the turbulent flames under low turbulent intensity. These research results provide a theoretical basis for the practical application of syngas with a complex composition in gas turbine power generation.

Measurements of Stretch Statistics at Flame Leading Points for High Hydrogen Content Fuels

2014 ◽  
Author(s):  
Andrew Marshall ◽  
Julia Lundrigan ◽  
Prabhakar Venkateswaran ◽  
Jerry Seitzman ◽  
Tim Lieuwen
Keyword(s):  
Flame Front ◽  
Hydrogen Content ◽  
Turbulent Flame ◽  
Flame Speed ◽  
Fuel Composition ◽  
Mean Flow ◽  
Tangential Strain ◽  
High Hydrogen ◽  
High Hydrogen Content ◽  
Turbulent Flame Speed

Fuel composition has a strong influence on the turbulent flame speed, even at very high turbulence intensities. An important implication of this result is that the turbulent flame speed cannot be extrapolated from one fuel to the next using only the laminar flame speed and turbulence intensity as scaling variables. This paper presents curvature and tangential strain rate statistics of premixed turbulent flames for high hydrogen content fuels. Global (unconditioned) stretch statistics are presented as well as measurements conditioned on the leading points of the flame front. These measurements are motivated by previous experimental and theoretical work that suggests the turbulent flame speed is controlled by the flame front characteristics at these points. The data were acquired with high speed particle image velocimetry (PIV) in a low swirl burner (LSB). We attained measurements for several H2:CO mixtures over a range of mean flow velocities and turbulence intensities. The results show that fuel composition has a systematic, yet weak effect on curvatures and tangential strain rates at the leading points. Instead, stretch statistics at the leading points are more strongly influenced by mean flow velocity and turbulence level. It has been argued that the increased turbulent flame speeds seen with increasing hydrogen content are the result of increasing flame stretch rates, and therefore SL,max values, at the flame leading points. However, the differences observed with changing fuel compositions are not significant enough to support this hypothesis. Additional analysis is needed to understand the physical mechanisms through which the turbulent flame speed is altered by fuel composition effects.

Study of Fuel Composition Effects on Flashback Using a Confined Jet Flame Burner

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Brendan Shaffer ◽  
Zhixuan Duan ◽  
Vincent McDonell
Keyword(s):  
Natural Gas ◽  
Laminar Flame ◽  
Flame Temperature ◽  
Flame Speed ◽  
Fuel Composition ◽  
Laminar Flame Speed ◽  
Processing Scheme ◽  
High Hydrogen ◽  
Jet Flame ◽  
Wide Range

Flashback is the main operability issue associated with converting lean, premixed combustion systems from operation on natural gas to operation on high hydrogen content fuels. Most syngas fuels contain some amount of hydrogen (15–100%) depending on the fuel processing scheme. With this variability in the composition of syngas, the question of how fuel composition impacts flashback propensity arises. To address this question, a jet burner configuration was used to develop systematic data for a wide range of compositions under turbulent flow conditions. The burner consisted of a quartz burner tube confined by a larger quartz tube. The use of quartz allowed visualization of the flashback processes occurring. Various fuel compositions of hydrogen, carbon monoxide, and natural gas were premixed with air at equivalence ratios corresponding to constant adiabatic flame temperatures (AFT) of 1700 K and 1900 K. Once a flame was stabilized on the burner, the air flow rate would be gradually reduced while holding the AFT constant via the equivalence ratio until flashback occurred. Schlieren and intensified OH* images captured at high speeds during flashback allowed some additional understanding of what is occurring during the highly dynamic process of flashback. Confined and unconfined flashback data were analyzed by comparing data collected in the present study with existing data in the literature. A statistically designed test matrix was used which allows analysis of variance of the results to be carried out, leading to correlation between fuel composition and flame temperature with (1) critical flashback velocity gradient and (2) burner tip temperature. Using the burner tip temperature as the unburned temperature in the laminar flame speed calculations showed increased correlation of the flashback data and laminar flame speed as opposed to when the actual unburned gas temperature was used.

Flashback Limits of Premixed H2/CH4 Flames in a Swirl-Stabilized Combustor

2010 ◽  
Author(s):  
Nasser Shelil ◽  
Anthony Griffiths ◽  
Audrius Bagdanavicius ◽  
Nick Syred
Keyword(s):  
Atmospheric Pressure ◽  
Laminar Flame ◽  
Flame Speed ◽  
Cfd Modeling ◽  
Pure Hydrogen ◽  
Laminar Flame Speed ◽  
Operating Pressure ◽  
Mixture Ratio ◽  
Fuel Blends ◽  
Pure Methane

CFD modeling is used to simulate the combustion and flashback behavior of H2/CH4 fuel blends with air in a premixed swirl burner using a three dimensional–finite volume model. Preliminary work was performed to calculate the laminar flame speed for H2/CH4 blends from pure methane up to pure hydrogen at various pressures, temperatures and equivalence ratios by using CHEMKIN, for pure fuels, and a new approximation based on the gravimetric mixture ratio, for the fuel blends. Then, the numerical values for laminar flame speed were fed to a FLUENT CFD model to create a PDF table for turbulent premixed combustion calculations and flashback studies. Flashback limits were defined and determined for H2/CH4 blends ranging from 0% (pure methane) up to 100% (pure hydrogen) based on the volumetric composition at atmospheric pressure and 300K for various equivalence ratios. The simulations were compared with experimental measurements at atmospheric pressure for two fuel blends with γ of 0.15 and 0.3 and showed best fit for equivalence ratios less than 0.75 to 0.8. The work was then extended to include simulation studies to investigate the effect of operating pressure and raw gases temperature on flame stability and showed a high dependence on both operating pressure and raw gases temperature.

Study of Fuel Composition Effects on Flashback Using a Confined Jet Flame Burner

2012 ◽  
Author(s):  
Brendan Shaffer ◽  
Zhixuan Duan ◽  
Vincent McDonell
Keyword(s):  
Natural Gas ◽  
Laminar Flame ◽  
Flame Temperature ◽  
Flame Speed ◽  
Fuel Composition ◽  
Laminar Flame Speed ◽  
Processing Scheme ◽  
High Hydrogen ◽  
Jet Flame ◽  
Wide Range

Flashback is the main operability issue associated with converting lean, premixed combustion systems from operation on natural gas to operation on high hydrogen content fuels. Most syngas fuels contain some amount of hydrogen (15–100%) depending on the fuel processing scheme. With this variability in the composition of syngas, the question of how fuel composition impacts flashback propensity arises. To address this question, a jet burner configuration was used to develop systematic data for a wide range of compositions under turbulent flow conditions. The burner consisted of a quartz burner tube confined by a larger quartz tube. The use of quartz allowed visualization of the flashback processes occurring. Various fuel compositions of hydrogen, carbon monoxide, and natural gas were premixed with air at equivalence ratios corresponding to constant adiabatic flame temperatures (AFT) of 1700 K and 1900 K. Once a flame was stabilized on the burner, the air flow rate would be gradually reduced while holding the AFT constant via the equivalence ratio until flashback occurred. Schlieren and intensified OH* images captured at high speeds during flashback allowed some additional understanding of what is occurring during the highly dynamic process of flashback. Confined and unconfined flashback data were analyzed by comparing data collected in the present study with existing data in the literature. A statistically designed test matrix was used which allows analysis of variance of the results to be carried out, leading to correlation between fuel composition and flame temperature with (1) critical flashback velocity gradient and (2) burner tip temperature. Using the burner tip temperature as the unburned temperature in the laminar flame speed calculations showed increased correlation of the flashback data and laminar flame speed as opposed to when the actual unburned gas temperature was used.

Measurements of Stretch Statistics at Flame Leading Points for High Hydrogen Content Fuels

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Andrew Marshall ◽  
Julia Lundrigan ◽  
Prabhakar Venkateswaran ◽  
Jerry Seitzman ◽  
Tim Lieuwen
Keyword(s):  
Flame Front ◽  
Hydrogen Content ◽  
Turbulent Flame ◽  
Flame Speed ◽  
Fuel Composition ◽  
Mean Flow ◽  
Tangential Strain ◽  
High Hydrogen ◽  
High Hydrogen Content ◽  
Turbulent Flame Speed

Fuel composition has a strong influence on the turbulent flame speed, even at very high turbulence intensities. An important implication of this result is that the turbulent flame speed cannot be extrapolated from one fuel to the next using only the laminar flame speed and turbulence intensity as scaling variables. This paper presents curvature and tangential strain rate statistics of premixed turbulent flames for high hydrogen content (HHC) fuels. Global (unconditioned) stretch statistics are presented as well as measurements conditioned on the leading points of the flame front. These measurements are motivated by previous experimental and theoretical work that suggests the turbulent flame speed is controlled by the flame front characteristics at these points. The data were acquired with high-speed particle image velocimetry (PIV) in a low-swirl burner (LSB). We attained measurements for several H2:CO mixtures over a range of mean flow velocities and turbulence intensities. The results show that fuel composition has a systematic, yet weak effect on curvatures and tangential strain rates at the leading points. Instead, stretch statistics at the leading points are more strongly influenced by mean flow velocity and turbulence level. It has been argued that the increased turbulent flame speeds seen with increasing hydrogen content are the result of increasing flame stretch rates, and therefore, SL,max values, at the flame leading points. However, the differences observed with changing fuel compositions are not significant enough to support this hypothesis. Additional analysis is needed to understand the physical mechanisms through which the turbulent flame speed is altered by fuel composition effects.

Turbulent Consumption Speeds of High Hydrogen Content Fuels From 1–20 atm

2013 ◽  
Author(s):  
Prabhakar Venkateswaran ◽  
Andrew D. Marshall ◽  
Jerry M. Seitzman ◽  
Tim C. Lieuwen
Keyword(s):  
Burning Rate ◽  
Hydrogen Content ◽  
Pressure Effects ◽  
Pressure Sensitivity ◽  
Mass Burning Rate ◽  
High Hydrogen ◽  
High Hydrogen Content ◽  
Fuel Blends ◽  
Correlate Data

This work describes measurements and analysis of the turbulent consumption speeds, ST,GC, of H2/CO fuel blends. We report measurements of ST,GC at pressures and normalized turbulence intensities, u′rms/SL,0 up to 20 atm and 1800, respectively for a variety of H2/CO mixtures and equivalence ratios. In addition, we present correlations of these data using laminar burning velocities of highly stretched flames, SL,max, derived from quasi-steady leading points models. These analyses show that SL,max can be used to correlate data over a broad range of fuel compositions, but do not capture the pressure sensitivity of ST,GC. We suggest that these pressure effects are more fundamentally a manifestation of non-quasi-steady behavior in the mass burning rate at the flame leading points.

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.

scholarly journals Production of JET fuel containing molecules of high hydrogen content

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Sz. Tomasek ◽  
Z. Varga ◽  
A. Holló ◽  
N. Miskolczi ◽  
J. Hancsók
Keyword(s):  
Hydrogen Content ◽  
Alternative Fuels ◽  
Jet Fuel ◽  
Plastic Waste ◽  
High Hydrogen ◽  
High Hydrogen Content ◽  
Waste Polyethylene ◽  
Harmful Effects

AbstractThe harmful effects of aviation can only be reduced by using alternative fuels with excellent burning properties and a high hydrogen content in the constituent molecules. Due to increasing plastic consumption the amount of the plastic waste is also higher. Despite the fact that landfill plastic waste has been steadily reduced, the present scenario is not satisfactory. Therefore, the aim of this study is to produce JET fuel containing an alternative component made from straight-run kerosene and the waste polyethylene cracking fraction. We carried out our experiments on a commercial NiMo/Al

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