Modeling of vented hydrogen-air deflagrations and correlations for vent sizing

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

doi:10.1016/s0950-4230(98)00049-7

Cited by 69 publications

(26 citation statements)

References 20 publications

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“…3 (right) shows comparison between the novel correlation, both best fit and conservative lines are shown, and previous best fit correlation of 1999 [4] and conservative correlation of 2001/2008 [6,7,9]. The slope of new correlation is not so steep relative to former correlations.…”

Section: Experimental Database For Validation Of the Correlationmentioning

confidence: 94%

“…The correlation for low-strength equipment and buildings, i.e. when the deflagration overpressure or reduced pressure is below 0.1 MPa (initial pressure in such cases is usually atmospheric equal to 0.1 MPa), is presented by from our 1999 study [4] that is the best fit to experimental data…”

Section: Introductionmentioning

confidence: 96%

“…Acronyms CFD computational fluid dynamics DOI deflagrationeoutflow interaction LES large eddy simulation SGS sub-grid scale i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 0 ( 2 0 1 5 ) 1 2 5 6 e1 2 6 6 deflagrations [7,9] compared to the best fit correlation of 1999 [4]. The empirical coefficients for calculation of the DOI number were different for hydrocarboneair and hydrogeneair mixtures in the 2001 correlation.…”

Section: Introductionmentioning

confidence: 99%

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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 Correlationmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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

Molkov

Bragin

2015

International Journal of Hydrogen Energy

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“…It was shown that the gas flow turbulence increased the flame propagating velocity and made the pressure rise rapidly. Molkov [11,12] achieved a reasonable comparison with experimental data for very high values of the deflagration-outflow-interaction number / χ u , results showed that internal obstacles, mixed gas concentration and vessel volume all had influence on the flame surface. Kobiera et al [2] gave a new phenomenological model in a closed vessel, which is based on the assumption that the burning velocity of a turbulent wrinkled flame could be determined by the flame surface.…”

Section: Related Research Achievementsmentioning

confidence: 81%

Mechanical model of domestic gas explosion load

Han

Chen

2008

Trans. Tianjin Univ.

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Abstract：With the increase of domestic gas consumption in cities and towns in China, gas explosion accidents happened rather frequently, and many structures were damaged greatly. Rational physical design could protect structures from being destroyed, but the character of explosion load must be learned firstly by establishing a correct mechanical model to simulate vented gas explosions. The explosion process has been studied for many years towards the safety of chemical industry equipments. The key problem of these studies was the equations usually involved some adjustable parameters that must be evaluated by experimental data, and the procedure of calculation was extremely complicated, so the reliability of these studies was seriously limited. Based on these studies, a simple mathematical model was established in this paper by using energy conservation, mass conservation, gas state equation, adiabatic compression equation and gas venting equation. Explosion load must be estimated by considering the room layout; the rate of pressure rise was then corrected by using a turbulence factor, so the pressure-time curve could be obtained. By using this method, complicated calculation was avoided, while experimental and calculated results fitted fairly well. Some pressure-time curves in a typical rectangular room were calculated to investigate the influences of different ignition locations, gas thickness, concentration, room size and venting area on the explosion pressure. The results indicated that: it was the most dangerous condition when being ignited in the geometry centre of the room; the greater the burning velocity, the worse the venting effect; the larger the venting pressure, the higher the peak pressure; the larger the venting area, the lower the peak pressure.

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“…There are a number of empirical and semi-empirical methods that can be used for the sizing of explosion venting [2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%