Effects of water sprays on flame propagation in hydrogen/air/steam mixtures

Cheikhravat, Homan; Goulier, J.; Boutarfaïa, Ahmed; Meynet, N.; Chaumeix, Nabiha; Paillard, C.

doi:10.1016/j.proci.2014.05.102

Cited by 33 publications

(5 citation statements)

References 31 publications

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“…The results of these projects contribute to enhance the level of knowledge on flammability limits [22], on the FA criteria in semi-confined configuration [19] and in nonhomogenous mixtures [22]. The effect of spray on flame propagation has also been partially addressed [23,24].…”

Section: Hydrogen Combustionmentioning

confidence: 99%

Overview on hydrogen risk research and development activities: Methodology and open issues

Boutarfaïa

Meynet

Bleyer

2015

Nuclear Engineering and Technology

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a b s t r a c tDuring the course of a severe accident in a light water nuclear reactor, large amounts of hydrogen can be generated and released into the containment during reactor core degradation. Additional burnable gases [hydrogen (H 2 ) and carbon monoxide (CO)] may be released into the containment in the corium/concrete interaction. This could subsequently raise a combustion hazard. As the Fukushima accidents revealed, hydrogen combustion can cause high pressure spikes that could challenge the reactor buildings and lead to failure of the surrounding buildings. To prevent the gas explosion hazard, most mitigation strategies adopted by European countries are based on the implementation of passive autocatalytic recombiners (PARs). Studies of representative accident sequences indicate that, despite the installation of PARs, it is difficult to prevent at all times and locations, the formation of a combustible mixture that potentially leads to local flame acceleration.Complementary research and development (R&D) projects were recently launched to understand better the phenomena associated with the combustion hazard and to address the issues highlighted after the Fukushima Daiichi events such as explosion hazard in the venting system and the potential flammable mixture migration into spaces beyond the primary containment. The expected results will be used to improve the modeling tools and methodology for hydrogen risk assessment and severe accident management guidelines.The present paper aims to present the methodology adopted by Institut de Radioprotection et de Sû ret e Nucl eaire to assess hydrogen risk in nuclear power plants, in particular French nuclear power plants, the open issues, and the ongoing R&D programs related to hydrogen distribution, mitigation, and combustion.

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Section: Hydrogen Combustionmentioning

confidence: 99%

Overview on hydrogen risk research and development activities: Methodology and open issues

Boutarfaïa

Meynet

Bleyer

2015

Nuclear Engineering and Technology

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“…To mitigate the influence of hydrogen explosion, the addition of inert gas is well-known to be one of possible approaches. We have several reports which experimentally studied the effects of inert-gas addition on the combustion characteristics of hydrogen premixtures (Qiao et al, 2007;Bane et al, 2011;Zhang et al, 2012;Cheikhravat et al, 2015;Duan and Liu, 2017;Li et al, 2018;Li et al, 2019;Yan et al, 2020;Gong et al, 2020;Katsumi et al, 2021;Morovatiyan, et al, 2021). The addition of inert gas has the effects of decreasing the burning velocity and reducing the maximum pressure in explosion.…”

Section: Introductionmentioning

confidence: 99%

Effects of inert-gas addition on the dynamic behavior and propagation characteristics of spherically expanding hydrogen-air flames

KATSUMI,

KUMADA,

NOGUCHI

et al. 2023

JTST

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To investigate the effects of inert-gas addition on the dynamic behavior and propagation characteristics of spherically expanding hydrogen-air flames, the experiments of premixed combustion were performed in a closed chamber. The dynamic behavior of premixed flames was caught by high-speed Schlieren imaging, and the flame radius and propagation velocity were measured by analyzing the Schlieren photography. When the flame radius was sufficiently small, smooth flame surface was observed, where the flame stretch affected strongly the propagation velocity. From the correlation between the propagation velocity and flame stretch rate, we estimated the propagation velocity of unstretched flame and the Markstein length including thermal-expansion effects. When the flame radius was large, on the other hand, cellular surface induced by intrinsic instability was observed, and then the flame acceleration was confirmed. As the results, the critical flame radius corresponding to the occurrence of flame acceleration and the increment coefficient of propagation velocity were obtained. It was found that the increment coefficient became larger at low equivalence ratios, which was because the diffusivethermal instability became stronger. Under the conditions of high concentration of inert gas, the increment coefficient of propagation velocity became smaller. This was because the burning velocity became lower by increasing the inert-gas concentration. Moreover, we obtained the increment coefficient normalized by the propagation velocity of unstretched flame. The normalized increment coefficient increased as the inert-gas concentration became higher, which indicated that the addition of inert gas promoted the instability of hydrogen flames. Based on the dynamic behavior and propagation characteristics of premixed flames, the parameters of flame acceleration model depending on the inert-gas concentration were obtained, and then the flame propagation velocity was predicted.

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“…Meanwhile, Gieras et al 19 and Cheikhravat et al 20 found that the turbulence generated by water mist would accelerate ame propagation. Yu et al 21 pointed out that adequate water mist could effectively reduce the explosion intensity, but it would increase the explosion intensity when the water mist was insufficient.…”

Section: Introductionmentioning

confidence: 99%

Synergistic inhibition effect on the self-acceleration characteristics in the initial stage of methane/air explosion by CO₂ and ultrafine water mist

et al. 2019

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Effects of water sprays on flame propagation in hydrogen/air/steam mixtures

Cited by 33 publications

References 31 publications

Overview on hydrogen risk research and development activities: Methodology and open issues

Overview on hydrogen risk research and development activities: Methodology and open issues

Effects of inert-gas addition on the dynamic behavior and propagation characteristics of spherically expanding hydrogen-air flames

Synergistic inhibition effect on the self-acceleration characteristics in the initial stage of methane/air explosion by CO₂ and ultrafine water mist

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Effects of water sprays on flame propagation in hydrogen/air/steam mixtures

Cited by 33 publications

References 31 publications

Overview on hydrogen risk research and development activities: Methodology and open issues

Overview on hydrogen risk research and development activities: Methodology and open issues

Effects of inert-gas addition on the dynamic behavior and propagation characteristics of spherically expanding hydrogen-air flames

Synergistic inhibition effect on the self-acceleration characteristics in the initial stage of methane/air explosion by CO2 and ultrafine water mist

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Synergistic inhibition effect on the self-acceleration characteristics in the initial stage of methane/air explosion by CO₂ and ultrafine water mist