Laminar flame properties of C1-C3 alkanes/hydrogen blends at gas engine conditions

Kuppa, Kalyan; Goldmann, Andreas; Schöffler, Tobias; Dinkelacker, Friedrich

doi:10.1016/j.fuel.2018.02.167

Cited by 22 publications

(5 citation statements)

References 43 publications

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“…At any hydrogen concentration, the burning velocities of NG-H2-air are smaller than those of CH4-H2-air, as a consequence of the presence of heavier hydrocarbons in NG. Both experimental and modeling studies on the effect of hydrogen addition to the C2, C3, or C4 alkanes [3,8,[19][20][21]69,70] showed that the enhancement of LBV upon the addition of 50% H2 was about 20-40% lower compared to when the fuel was pure methane. The computed LBV can be compared to present experimental LBVs when plotted as functions of the equivalence ratios of H2-blended CH4-air and NG-air mixtures, as shown in Figure 5.…”

Section: Resultsmentioning

confidence: 99%

“…Hydrogen raises numerous safety issues, especially when mixed with other flammable gases. The main cause of such effects is the higher reactivity of H 2 compared to each C 1 -C 4 alkanes from NG, resulting in important variations of ignition and propagation characteristic parameters of NG-air combustion: decreases in ignition delay times of selfignition and minimum ignition energies, increases in adiabatic flame temperature and in laminar burning velocity [9,11,20,21]. Taking into account the variable composition of NG as a result of current changes in its supplies, many studies were conducted on CH 4 /H 2 /air flames [8,11,13,14,[19][20][21][22][23][24][25][26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

“…The main cause of such effects is the higher reactivity of H 2 compared to each C 1 -C 4 alkanes from NG, resulting in important variations of ignition and propagation characteristic parameters of NG-air combustion: decreases in ignition delay times of selfignition and minimum ignition energies, increases in adiabatic flame temperature and in laminar burning velocity [9,11,20,21]. Taking into account the variable composition of NG as a result of current changes in its supplies, many studies were conducted on CH 4 /H 2 /air flames [8,11,13,14,[19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Such studies revealed the effect of H 2 enrichment: enlargement of the flammability range of CH 4 -air mixtures [11,13,14], decreases in ignition delay times in jet-stirred reactors, rapid compression machines or shock tubes [21,26,30], decreases in maximum experimental safe gap (MESG) [11], and increases in flame speed and laminar burning velocity [8,[22][23][24][25][26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

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Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

2021

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The flammable hydrogen-blended methane–air and natural gas–air mixtures raise specific safety and environmental issues in the industry and transportation; therefore, their explosion characteristics such as the explosion limits, explosion pressures, and rates of pressure rise have significant importance from a safety point of view. At the same time, the laminar burning velocities are the most useful parameters for practical applications and in basic studies for the validation of reaction mechanisms and modeling turbulent combustion. In the present study, an experimental and numerical study of the effect of hydrogen addition on the laminar burning velocity (LBV) of methane–air and natural gas–air mixtures was conducted, using mixtures with equivalence ratios within 0.90 and 1.30 and various hydrogen fractions rH within 0.0 and 0.5. The experiments were performed in a 14 L spherical vessel with central ignition at ambient initial conditions. The LBVs were calculated from p(t) data, determined in accordance with EN 15967, by using only the early stage of flame propagation. The results show that hydrogen addition determines an increase in LBV for all examined binary flammable mixtures. The LBV variation versus the fraction of added hydrogen, rH, follows a linear trend only at moderate hydrogen fractions. The further increase in rH results in a stronger variation in LBV, as shown by both experimental and computed LBVs. Hydrogen addition significantly changes the thermal diffusivity of flammable CH4–air or NG–air mixtures, the rate of heat release, and the concentration of active radical species in the flame front and contribute, thus, to LBV variation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

2021

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“…For premixed lean burn gas engines, the combustion models strongly rely on laminar and turbulent flame speed [102]. Though research has been done during the last years to provide data on the high-temperature chemistry and the interaction with turbulence [102,103], an extension of this database to high pressures beyond 10 MPa as well as very lean mixtures and low laminar flame speeds is still needed [104]. Simulations of an un-scavenged prechamber with the G-equation model revealed that the turbulence/flame-interaction differed significantly from the conditions in the main chamber and an extended formulation of the turbulent flame speed was necessary [105].…”

Section: Flame Propagationmentioning

confidence: 99%

Towards a Predictive Simulation of Turbulent Combustion?—An Assessment for Large Internal Combustion Engines

Lauer

Frühhaber

2020

Energies

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Frequently the question arises in what sense numerical simulation can be considered predictive if prior model tuning with test results is necessary. In this paper a summary of the present Computational Fluid Dynamics (CFD) simulation methods for in-cylinder modelling is presented with a focus on combustion processes relevant for large engines. The current discussion about the sustainability of internal combustion engines will have a strong impact on applying advanced CFD methods in industrial processes. It is therefore included in the assessment. Simplifications and assumptions of turbulence, spray, and combustion models, as well as uncertainties of model boundary conditions, are discussed and the future potential of an advanced approach like Large Eddy Simulation (LES) is evaluated. It follows that a high amount of expertise and a careful evaluation of the numerical results will remain necessary in the future to apply the best-suited models for a given combustion process. New chemical mechanisms will have to be developed in order to represent prospective fuels like hydrogen or OME. Multi-injection or dual fuel combustion will further pose high requirements to the numerical methods. Therefore, the further development and validation of advanced mixture, combustion and emission models will remain important. Close cooperation between academia, code suppliers and engine manufacturers could promote the necessary progress.

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“…It is acknowledged that the high reactivity of hydrogen will raise multiple safety concerns when blended with ethane, methane, and propane. These effects also lead to significant changes in the ignition and propagation characteristic parameters of NG/H 2 /air flames: a reduction in minimum ignition energies and self-ignition delay times, alongside the growth in adiabatic flame temperatures and laminar burning velocity [13][14][15][16]. Several studies have revealed the effects of H 2 on natural gas components, including the broadening of the flammability limits of CH 4 /air flames [13,17,18] and increases in S L [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Kinetic Study on Laminar Burning Velocities of High Ratio Hydrogen Addition to CH4+O2+N2 and NG+O2+N2 Flames

Zhang

Zhu

et al. 2023

Energies

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In 2020, energy-related CO2 emissions reached 31.5 Gt, leading to an unprecedented atmospheric CO2 level of 412.5 ppm. Hydrogen blending in natural gas (NG) is a solution for maximizing clean energy utilization and enabling long-distance H2 transport through pipelines. However, insufficient comprehension concerning the combustion characteristics of NG, specifically when blended with a high proportion of hydrogen up to 80%, particularly with minority species, persists. Utilizing the heat flux method at room temperature and 1 atm, this experiment investigated the laminar burning velocities of CH4/NG/H2/air/He flames incorporating minority species, specifically C2H6 and C3H8, within NG. The results point out the regularity of SL enhancement, reaching its maximum at an equivalence ratio of 1.4. Furthermore, the propensity for the enhancement of laminar burning velocity aligned with the observed thermoacoustic oscillation instability during fuel-rich regimes. The experimental findings were contrasted with kinetic simulations, utilizing the GRI 3.0 and San Diego mechanisms to facilitate analysis. The inclusion of H2 augments the chemical reactions within the preheating zone, while the thermal effect from temperature is negligible. Both experimental and simulated results revealed that CH4 and NG with a large proportion of H2 had no difference, no matter whether from a laminar burning velocity or a kinetic analysis aspect.

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Laminar flame properties of C1-C3 alkanes/hydrogen blends at gas engine conditions

Cited by 22 publications

References 43 publications

Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

Towards a Predictive Simulation of Turbulent Combustion?—An Assessment for Large Internal Combustion Engines

Experimental and Kinetic Study on Laminar Burning Velocities of High Ratio Hydrogen Addition to CH4+O2+N2 and NG+O2+N2 Flames

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