Venting of deflagrations: hydrocarbon–air and hydrogen–air systems

Molkov, Vladimir; Dobashi, Ritsu; Suzuki, Masashi; Hirano, Toshisuke

doi:10.1016/s0950-4230(99)00063-7

Cited by 59 publications

(28 citation statements)

References 24 publications

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“…The DOI number does not depend on the enclosure size following former correlation (5) by Tufano et al [25] and increases with enclosure scale following our correlation (6) if the Bradley number or its analogy in correlation (5) are constant. It has been shown previously [5] that correlation (6) complies with the conclusion of Gouldin [27], who applied the fractal theory for turbulent flame modelling, that the flame surface of a turbulent outward propagating flame grows not as square of the flame radius, R 2 , but faster as R 2 R DÀ2 . Here D is the fractal dimension which has theoretical value equal to 7/3 and measured value in the range 2.11e2.37 [11].…”

Section: Experimental Database For Validation Of the Correlationsupporting

confidence: 77%

Hydrogen–air deflagrations: Vent sizing correlation for low-strength equipment and buildings

Molkov

Bragin

2015

International Journal of Hydrogen Energy

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a b s t r a c t This paper aims to improve prediction capability of the vent sizing correlation presented in the form of functional dependence of the dimensionless deflagration overpressure on the turbulent Bradley number similar to our previous studies. The correlation is essentially upgraded based on recent advancements in understanding and modelling of combustion phenomena relevant to hydrogeneair vented deflagrations and unique large-scale tests carried out by different research groups. The focus is on hydrogeneair deflagrations in low-strength equipment and buildings when the reduced pressure is accepted to be below 0.1 MPa. The combustion phenomena accounted for by the correlation include: turbulence generated by the flame front itself; leading point mechanism stemming from the preferential diffusion of hydrogen in air in stretched flames; growth of the fractal area of the turbulent flame surface; initial turbulence in the flammable mixture; as well as effects of enclosure aspect ratio and presence of obstacles. The correlation is validated against the widest range of experimental conditions available to date (76 experimental points). The validation covers a wide range of test conditions: different shape enclosures of volume up to 120 m 3 ; initially quiescent and turbulent hydrogeneair mixtures; hydrogen concentration in air from 6% to 30% by volume; ignition source location at enclosure centre, near and far from a vent; empty enclosures and enclosures with obstacles.

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Section: Experimental Database For Validation Of the Correlationsupporting

confidence: 77%

Hydrogen–air deflagrations: Vent sizing correlation for low-strength equipment and buildings

Molkov

Bragin

2015

International Journal of Hydrogen Energy

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“…Zero-dimensional models proved effective in advancing the comprehension and the formalization of data gained for simply vented explosions [19][20][21]. Zero-dimensional and onedimensional models [4,17] were also proposed to represent an explosion vented through a duct but result in a scarce predictive capability as they rely strongly on empirical parameters.…”

Section: Introductionmentioning

confidence: 99%

“…Due to their empirical foundation, NFPA correlations are to be used very carefully as they can lead to gross errors [20].…”

Section: Introductionmentioning

confidence: 99%

CFD analysis of gas explosions vented through relief pipes

Ferrara

Benedetto

Salzano

et al. 2006

Journal of Hazardous Materials

122

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“…The cited works of Ponizy and Leyer and later of Ponizy and Veyssiere [10] are prominent as they represent a most comprehensive set of experimental data for this venting configuration and give a big contribution to the understanding of the phenomenon. These works are based on a small 3.6 l vessel and it is not possible to know if the findings at this small scale are applicable to larger more industrially relevant scales given the well known importance and difficulties of scale effects in explosion dynamics [11,12,13].…”

Section: Introductionmentioning

confidence: 99%

Duct-vented Propaneiair Explosions With Central And Rear Ignition

Ferrara¹,

Benedetto²,

Willacy³

et al. 2005

Fire Safety Science - Proceedings of the Eigth International Sy

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It is commonplace in industrial installations to have duct vented vessels, the design of which is often based upon the premise that central ignition will provide the worst case scenario. This research investigates duct-vented explosions using a vented test chamber of 200 l capacity fitted with a 1m long vent pipe, discharging into a large (50 m 3 ) dump volume with rear and central ignition. Propane-air mixtures over a range of concentrations (Ф=0.8-1.6) have been used. Results show that while there is no significant difference in maximum pressure in the test vessel for rear and central ignition, rear ignition consistently produces the worst case in terms of rates of pressure rise and flame-speeds in the duct. In addition, the detailed records of pressure traces and flame position showed a direct relationship between the induced gas velocity in the duct prior to the flame arrival and the subsequent rate of pressure rise in the vessel. The implications of the findings for practical systems are briefly discussed.

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Venting of deflagrations: hydrocarbon–air and hydrogen–air systems

Cited by 59 publications

References 24 publications

Hydrogen–air deflagrations: Vent sizing correlation for low-strength equipment and buildings

Hydrogen–air deflagrations: Vent sizing correlation for low-strength equipment and buildings

CFD analysis of gas explosions vented through relief pipes

Duct-vented Propaneiair Explosions With Central And Rear Ignition

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