Fire | Special Issue : State-of-the-Art on Hydrogen Combustion

Research

15 pages, 586 KiB

Open AccessArticle

State-to-State Rate Constants for the O(³P)H₂(v) System: Quasiclassical Trajectory Calculations

by Alexey V. Pelevkin, Ilya V. Arsentiev, Ilya N. Kadochnikov, Ivan A. Zubrilin, Evgeny P. Filinov and Denis V. Yakushkin

Fire 2024, 7(7), 220; https://doi.org/10.3390/fire7070220 - 28 Jun 2024

Viewed by 756

Abstract

The rate constants of elementary processes in the atom–diatom system

O (^{3} P) + H_{2} (v)

, including the processes of vibrational relaxation and dissociation, were studied using the quasiclassical trajectory method. All calculations were carried out along [...] Read more.

The rate constants of elementary processes in the atom–diatom system

O (^{3} P) + H_{2} (v)

, including the processes of vibrational relaxation and dissociation, were studied using the quasiclassical trajectory method. All calculations were carried out along the ground potential energy surface (PES) ³

A^{″}

that was approximated by a neural network. Approximation data were obtained using ab initio quantum chemistry methods at the extended multi-configuration quasi-degenerate second-order perturbation theory XMCQDPT2 in a basis set limit. The calculated cross-sections of the reaction channels are in good agreement with the literature data. A complete set of state-to-state rate constants was obtained for the metathesis reaction, the dissociation and relaxation of the H₂ molecule upon collision with an O atom. According to these data, Arrhenius approximations over a wide temperature range were obtained for the thermal rate constants of considered processes. Data obtained on the dissociation constants and VT relaxation of vibrationally excited H₂ molecules can be used in constructing kinetic models describing the oxidation of hydrogen at high temperatures or highly nonequilibrium conditions. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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25 pages, 8397 KiB

Open AccessArticle

Numerical Simulation and Consequence Analysis of Full-Scale Jet Fires for Pipelines Transporting Pure Hydrogen or Hydrogen Blended with Natural Gas

by Meng Li, Zhenhua Wang, Juncheng Jiang, Wanbing Lin, Lei Ni, Yong Pan and Guanghu Wang

Fire 2024, 7(6), 180; https://doi.org/10.3390/fire7060180 - 24 May 2024

Cited by 1 | Viewed by 1191

Abstract

The use of existing natural gas pipelines for the transport of hydrogen/natural gas mixtures can achieve large-scale, long-distance and low-cost hydrogen transportation. A jet fire induced by the leakage of high-pressure pure hydrogen and hydrogen-blended natural gas pipelines may pose a severe threat [...] Read more.

The use of existing natural gas pipelines for the transport of hydrogen/natural gas mixtures can achieve large-scale, long-distance and low-cost hydrogen transportation. A jet fire induced by the leakage of high-pressure pure hydrogen and hydrogen-blended natural gas pipelines may pose a severe threat to life and property. Based on the Abel–Nobel equation of state and a notional nozzle model, an equivalent pipe leakage model is established to simulate high-pressure pipeline gas leakage jet fire accidents. Large-scale high-pressure hydrogen and natural gas/hydrogen mixture jet fires are simulated, showing the jet impingement process and obtaining an accurate and effective simulation framework. This framework is validated by comparing the simulated and experimental measured results of flame height, flame appearance and thermal radiation. Several combustion models are compared, and the simulated data show that the non-premixed chemical equilibrium combustion model is superior to other combustion models. The influence of the pipe pressure and the hydrogen blending ratio on the consequences of natural gas/hydrogen mixture pipeline leakage jet fire accidents is explored. It is found that when the hydrogen blending ratio is lower than 22%, the increase in the hydrogen blending ratio has little effect on the decrease in the thermal radiation hazard distance. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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12 pages, 2663 KiB

Open AccessArticle

Ignition Delay and Reaction Time Measurements of Hydrogen–Air Mixtures at High Temperatures

by Yauhen Baranyshyn, Vyacheslav Kuzmitski, Oleg Penyazkov and Kirill Sevrouk

Fire 2024, 7(2), 43; https://doi.org/10.3390/fire7020043 - 30 Jan 2024

Cited by 1 | Viewed by 1963

Abstract

Induction and reaction times of hydrogen–air mixtures (ϕ = 0.5–2) have been measured behind reflected shock waves at temperatures of 1000–1600 K, pressures of 0.1, 0.3, 0.6 MPa in the domain of the extended second explosion limit. The measurements were performed in the [...] Read more.

Induction and reaction times of hydrogen–air mixtures (ϕ = 0.5–2) have been measured behind reflected shock waves at temperatures of 1000–1600 K, pressures of 0.1, 0.3, 0.6 MPa in the domain of the extended second explosion limit. The measurements were performed in the shock tube with a completely transparent test section of 0.5 m long, which provides pressure, ion current, OH and high-speed chemiluminescence observations. The experimental induction time plots demonstrate a clear increasing of the global activation energy from high- to low temperature post-shock conditions. This trend is strongly pronounced at higher post-shock pressures. For a high-temperature range of T > 1200 K, induction time measurements show an activation energy for the global reaction rate of hydrogen oxidation of 64–83 kJ/mole. Detected reaction times exhibit a big scatter and a weak temperature dependence. The minimum reaction time value was nearly 2 µs. Obtained induction time data were compared with calculations carried out in accordance with the known kinetic mechanisms. For current and former shock-tube experiments within a pressure range of 0.1–2 MPa, critical temperatures required for strong (1000–1100 K), transient and weak auto-ignition modes behind reflected shock waves were identified by means of the pressure and ion-probe measurements in stoichiometric hydrogen-air mixture. The transfer from the strong volumetric self-ignition near the reflecting wall to the hot spot ignition (transient) was established and visualized below <1200 K with a post-shock temperature decreasing. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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13 pages, 550 KiB

Open AccessArticle

Activation Energy of Hydrogen–Methane Mixtures

by Anastasia Moroshkina, Alina Ponomareva, Vladimir Mislavskii, Evgeniy Sereshchenko, Vladimir Gubernov, Viatcheslav Bykov and Sergey Minaev

Fire 2024, 7(2), 42; https://doi.org/10.3390/fire7020042 - 29 Jan 2024

Viewed by 2317

Abstract

In this work, the overall activation energy of the combustion of lean hydrogen–methane–air mixtures (equivalence ratio

φ

= 0.7−1.0 and hydrogen fraction in methane

α = 0

, 2, 4) is experimentally determined using thin-filament pyrometry of flames stabilised on a flat porous [...] Read more.

In this work, the overall activation energy of the combustion of lean hydrogen–methane–air mixtures (equivalence ratio

φ

= 0.7−1.0 and hydrogen fraction in methane

α = 0

, 2, 4) is experimentally determined using thin-filament pyrometry of flames stabilised on a flat porous burner under normal conditions (

p = 1

bar, T = 20 °C). The experimental data are compared with numerical calculations within the detailed reaction mechanism GRI3.0 and both approaches confirm the linear correlation between mass flow rate and inverse flame temperature predicted in the theory. An analysis of the numerical and experimental data shows that, in the limit of lean hydrogen–methane–air mixtures, the activation energy approaches a constant value, which is not sensitive to the addition of hydrogen to methane. The mass flow rate for a freely propagating flame and, thus, the laminar burning velocity, are measured for mixtures with different hydrogen contents. This mass flow rate, scaled over the characteristic temperature dependence of the laminar burning velocity for a one-step reaction mechanism, is found and it can also be used in order to estimate the parameters of the overall reaction mechanisms. Such reaction mechanisms will find implementation in the numerical simulation of practical combustion devices with complex flows and geometries. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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11 pages, 6377 KiB

Open AccessArticle

The Influence of Biofuels Addition on Shock-Induced Ignition and Combustion of Methane–Hydrogen Mixtures

by Alexander Drakon and Alexander Eremin

Fire 2023, 6(12), 460; https://doi.org/10.3390/fire6120460 - 4 Dec 2023

Cited by 1 | Viewed by 1493

Abstract

The ignition and combustion of three-component methane–hydrogen biofuel mixtures, considered as prospective fuels, were experimentally and numerically studied. Ignition delays in argon-diluted methane–hydrogen mixtures partially substituted with methanol or dimethyl ether were measured behind reflected shock waves in a temperature range of 1050–1900 [...] Read more.

The ignition and combustion of three-component methane–hydrogen biofuel mixtures, considered as prospective fuels, were experimentally and numerically studied. Ignition delays in argon-diluted methane–hydrogen mixtures partially substituted with methanol or dimethyl ether were measured behind reflected shock waves in a temperature range of 1050–1900 K at pressures of 3.5–5.5 bar. The obtained results were used for validation of modern kinetic mechanisms for hydrocarbons combustion. Numerical modeling of the combustion of the considered fuels in air at elevated pressures and temperatures was carried out, simulating typical engine compressed conditions, and the dependencies of key parameters such as flame velocity and temperature on fuel composition were obtained. The results of the study can be used in developing new energy technologies, reducing the environmental impact of hydrocarbon combustion. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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13 pages, 7151 KiB

Open AccessArticle

The Formation of a Flame Front in a Hydrogen–Air Mixture during Spark Ignition in a Semi-Open Channel with a Porous Coating

by Sergey Golovastov, Grigory Bivol, Fyodor Kuleshov and Victor Golub

Fire 2023, 6(12), 453; https://doi.org/10.3390/fire6120453 - 28 Nov 2023

Viewed by 1371

Abstract

An experimental study of ignition and flame front propagation during spark initiation in a hydrogen–air mixture in a semi-open channel with a porous coating is reported. The bottom surface of the channel was covered with a porous layer made of porous polyurethane or [...] Read more.

An experimental study of ignition and flame front propagation during spark initiation in a hydrogen–air mixture in a semi-open channel with a porous coating is reported. The bottom surface of the channel was covered with a porous layer made of porous polyurethane or steel wool. The measurements were carried out for a stoichiometric mixture (equivalence ratio ER = 1.0) and for a lean mixture (ER = 0.4) of hydrogen with air, where ER is the molar excess of hydrogen. The flame front was recorded with a high-speed camera using the shadow method. Depending on the pore size, the velocity of the flame front and the sizes of disturbances generated on the surface of the flame front were determined. Qualitative features of the deflagration flame front at ER = 0.4, consisting of disturbances resembling small balls of flame, were discovered. The sizes of these disturbances significantly exceed the analytical values for the Darrieus–Landau instability. The effect of coatings made of porous polyurethane or steel wool is compared with the results obtained for an empty smooth channel. Depending on the hydrogen concentration in the hydrogen–air mixture, the velocity of the flame front compared to a smooth channel was three times higher when the channel was covered with steel wool and five times higher when the channel was covered with porous polyurethane. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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12 pages, 2813 KiB

Open AccessArticle

Shock Tube Study of Ignition Delay Times for Hydrogen–Oxygen Mixtures

by Valery Pavlov, Gennady Gerasimov, Vladimir Levashov, Pavel Kozlov, Igor Zabelinsky and Natalia Bykova

Fire 2023, 6(11), 435; https://doi.org/10.3390/fire6110435 - 11 Nov 2023

Cited by 1 | Viewed by 2148

Abstract

This paper presents the results of measurements of ignition delay times in hydrogen–oxygen mixtures highly diluted with argon. The experiments were carried out behind an incident shock wave at temperatures from 870 to 2500 K, pressures from 0.5 to 1.5 atm, and equivalence [...] Read more.

This paper presents the results of measurements of ignition delay times in hydrogen–oxygen mixtures highly diluted with argon. The experiments were carried out behind an incident shock wave at temperatures from 870 to 2500 K, pressures from 0.5 to 1.5 atm, and equivalence ratios from 0.1 to 2.0. The results obtained were processed in terms of the partial pressure of the combustible mixture stoichiometric part that is consumed in the combustion process. An almost linear dependence of the ignition delay time on the reciprocal value of the partial pressure was found for both rich and lean mixtures. The measured data are compared with calculations based on the previously developed kinetic model and experimental data from other authors. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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12 pages, 1787 KiB

Open AccessArticle

Numerical Modeling of Hydrogen Combustion: Approaches and Benchmarks

by Ivan Yakovenko and Alexey Kiverin

Fire 2023, 6(6), 239; https://doi.org/10.3390/fire6060239 - 16 Jun 2023

Cited by 4 | Viewed by 1955

Abstract

The paper is devoted to the analysis of two different approaches for the numerical simulation of gaseous combustion. The first one is based on a full system of Navier-Stokes equations describing the dynamics of the compressible reactive medium, while the second one utilizes [...] Read more.

The paper is devoted to the analysis of two different approaches for the numerical simulation of gaseous combustion. The first one is based on a full system of Navier-Stokes equations describing the dynamics of the compressible reactive medium, while the second one utilizes low-Mach number approximation. The compressible model is realized by the traditional low-order numerical scheme and the contemporary CABARET method. The low-Mach approach is implemented on the base of a widely known FDS numerical scheme. The benefits and disadvantages of compressible and low-Mach approaches are discussed and demonstrated on a specially developed set of problem setups, applicable for validation and verification of the numerical methods for combustion analysis. In particular, the laminar flame velocity test, spherical bomb test, and multidimensional modeling of combustion development inside the rectangular closed vessel are performed via both techniques that allowed to determine the applicability limits of the low-Mach number approximation. Full article

(This article belongs to the Special Issue State-of-the-Art on Hydrogen Combustion)

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