Characterization of the flame front inversion of Ethanol–Air deflagrations inside A closed tube

Mendiburu, Andrés Z.; Serra, Aguinaldo M.; Andrade, José Carlos de; Silva, Lucas M.; Santos, José Carlos dos; Carvalho, João Andrade de

doi:10.1016/j.energy.2019.115932

Cited by 8 publications

(8 citation statements)

References 32 publications

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“…Furthermore, the flame front behavior for the third window has a cellular and irregular shape for all cases. This is in line with what is presented in the experimental observations and in the theory available in the literature. ,,, …”

Section: Resultssupporting

confidence: 92%

“…Note that the dimensionless position ξ tip,wall is measuring the distance traveled by the flame tip (from the ignition source) to the moment at which the planar flame front is starting to form. This distance has been discussed and measured in previous works. , The results of the integrations are given in eq . …”

Section: Methods and Theoretical Backgroundmentioning

confidence: 97%

“…The theoretical model developed by Valiev et al allows us to predict the flame speed at the early stages of flame propagation inside a duct closed at the ignition end. The model was applied by Mendiburu et al and Serra et al to compare the experimental results obtained for ethanol deflagrations inside borosilicate tubes. The assumptions made by Valiev et al are as follows: (a) duct walls are adiabatic, which permits the no-slip condition; (b) two-dimensional propagation analysis; (c) duct is closed at the ignition side; (d) incompressible flow in the first stage and moderate compression at the second stage; (e) rectangular geometry; and (f) potential flow.…”

Section: Methods and Theoretical Backgroundmentioning

confidence: 99%

“…The flame propagation inside a closed duct free of obstacles can be divided into five stages: (a) the spherical flame propagation, (b) the finger flame propagation (or acceleration stage), (c) the planar flame formation (or deceleration stage), (d) the tulip flame formation (or flame front inversion stage), and (e) the cellular flame propagation . Moreover, depending on the initial pressure, the flame propagation can enter the turbulent regime, as observed by Mendiburu et al In their work, Ponizy et al showed experimentally that the tulip flame is formed due to the reverse flow of the burned gases that stablishes inside the duct during the deceleration stage.…”

Section: Introductionmentioning

confidence: 95%

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Experimental and Theoretical Analyses of Deflagrations of Mixtures Involving Hydrogen Enrichment and Helium Dilution Inside a Closed Duct

Quines da Silva,

Lauermann,

Nzinga

et al. 2023

Energy Fuels

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The aim of the present work is to analyze experimentally and theoretically the deflagrations in a closed duct of mixtures in which natural gas is enriched with hydrogen or diluted with helium. In the first case, hydrogen would increase the flame propagation velocity, while in the second case, helium should make the mixture less reactive. The characterization of these mixtures is carried out with the help of Lewis (Le) and Zeldovich (Ze) numbers. Therefore, eight mixtures were considered. These mixtures covered a Le interval from 0.60 to 1.36 and a Ze interval from 4.24 to 8.45. Moreover, the mixtures involved species such as natural gas, hydrogen, helium, and air. It was observed that higher dimensionless flame tip velocities were obtained for mixtures with Le below unity. For mixtures with similar Le numbers, it was observed that lower Ze numbers produced higher velocities. A theoretical model available in the literature was applied and compared with the experimental data obtained in the present work for the dimensionless flame speed. It was noticed that the model presented greater discrepancies for mixtures with Le different from unity. The model was also applied to predict the evolution of the dimensionless flame tip position and was compared with published experimental data. Inaccuracies were observed for this comparison. In addition, two possible modifications of the existing theoretical model for determining the evolution of the dimensionless flame tip position are presented and validated in this paper. One of them showed good accuracy.

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Section: Resultssupporting

confidence: 92%

Section: Methods and Theoretical Backgroundmentioning

confidence: 97%

Section: Methods and Theoretical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

See 2 more Smart Citations

Experimental and Theoretical Analyses of Deflagrations of Mixtures Involving Hydrogen Enrichment and Helium Dilution Inside a Closed Duct

Quines da Silva,

Lauermann,

Nzinga

et al. 2023

Energy Fuels

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show abstract

“…Therefore, the flammable ranges tend to be larger for UFP than for DFP or HFP. Note that flames with HFP develop inverted flame fronts in closed vessels, also called tulip flames. , It is not clear how this phenomenon affects the experimental determination of FLs with HFP.…”

Section: Experimental Determination Of the Flammability Limitsmentioning

confidence: 99%

Flammability Limits: A Comprehensive Review of Theory, Experiments, and Estimation Methods

Mendiburu

Carvalho

2023

Energy Fuels

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Flammability limits play an important role in combustion research, industrial applications, and fire safety. This article provides a comprehensive review of recent developments in the fundamental understanding of flammability limits and their experimental determination as well as estimation methods for pure fuels and fuel mixtures. The article begins with a discussion of the importance and challenges of determining flammability limits. It then presents the theoretical, computational, and experimental methods available to understand the mechanism of flammability limits and to quantify them. The experimental setups using cylindrical and spherical vessels to determine the flammability limits are discussed. The effects of buoyancy, thermal radiation, and flame stretch are examined. The relationship between the fundamental flammability limits and the extinction limits of stretched flames via strain and radiation is presented. The effects of initial temperature, pressure, mixtures of different fuels, and diluents are examined, and available estimation methods are presented. Finally, the flammability limits of renewable and alternative fuels are addressed and strategies for estimating the flammability limits of these fuels are presented.

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Experimental observation of ethanol–air premixed flames propagating inside a closed tube with high aspect ratio

Serra

Andrade

Silva

et al. 2023

J Braz. Soc. Mech. Sci. Eng.

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Characterization of the flame front inversion of Ethanol–Air deflagrations inside A closed tube

Cited by 8 publications

References 32 publications

Experimental and Theoretical Analyses of Deflagrations of Mixtures Involving Hydrogen Enrichment and Helium Dilution Inside a Closed Duct

Experimental and Theoretical Analyses of Deflagrations of Mixtures Involving Hydrogen Enrichment and Helium Dilution Inside a Closed Duct

Flammability Limits: A Comprehensive Review of Theory, Experiments, and Estimation Methods

Experimental observation of ethanol–air premixed flames propagating inside a closed tube with high aspect ratio

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