Vented hydrogen–air deflagration in a small enclosed volume

Rocourt, Xavier; Awamat, S.; Sochet, Isabelle; Jallais, Simon

doi:10.1016/j.ijhydene.2014.03.233

Cited by 109 publications

(31 citation statements)

References 9 publications

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“…Contrary to the pressure profiles with multi-peaks in existing research (Schiavetti et al, 2014;Rocourt et al, 2014;Bauwens et al, 2011), only one dominant internal pressure peak was observed for all the equivalence ratios tested. As shown in Fig.…”

Section: Pressure Profile In Vesselcontrasting

confidence: 98%

“…As shown in Fig. 1, the first pressure peak 1 p , which can always be observed, results from the burst of the vent cover (Rocourt et al, 2014;Guo et al, 2015). The second pressure peak 2 p , which can be observed only for  = 1.0-2.0, is mainly due to the fast burning rate of the internal flames.…”

Section: Pressure Profile In Vesselmentioning

confidence: 79%

“…Apart from the aforementioned research, some aspects of the effect of hydrogen concentration on the process of explosion venting have not been studied yet. For example, only lean (Kumar et al, 1989;Bauwens et al, 2012;Kasmani, 2008) and stoichiometric (Rocourt et al, 2014) hydrogen-air mixtures were investigated, but the extent of the effect of hydrogen concentration on pressure history and flame behaviors of hydrogen-rich mixtures still remains unclear, which also deserves detailed investigation because any concentration of hydrogen-air mixtures between the lower and upper explosion limits can be attained in real life-for example, when hydrogen is accidentally leaked in a confined space.…”

Section: Introductionmentioning

confidence: 99%

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Experiments on vented hydrogen-air deflagrations: The influence of hydrogen concentration

Guo

Liu

Wang

2017

Journal of Loss Prevention in the Process Industries

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The explosion venting of hydrogen-air mixtures with equivalence ratios ranging from 0.4 to 6.0 was investigated in a small vented cylindrical vessel. The experimental results show that the maximum internal overpressure initially increases with an increase in hydrogen equivalence ratio up to approximately 1.6 and subsequently decreases. The discrepancy between the maximum internal overpressure and the vent burst pressure is significantly high for equivalence ratios ranging from 1.0 to 2.0 but low for very lean or very rich mixtures. Buoyancy has a significant effect on the evolution of the internal flame bubble for very lean hydrogen-air mixtures only. The speed of the external flame oscillates violently and its maximum value is achieved at a distance downstream from the vent. The maximum length of the flame ejected from the vent, which depends on the hydrogen equivalence ratio, may be underestimated by engineering models.

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Section: Pressure Profile In Vesselcontrasting

confidence: 98%

Section: Pressure Profile In Vesselmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

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Experiments on vented hydrogen-air deflagrations: The influence of hydrogen concentration

Guo

Liu

Wang

2017

Journal of Loss Prevention in the Process Industries

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“…Hence, there is a growing need for prediction and risk assessment tools for the safe design of many industrial structures and processes. However, the timing and magnitude of overpressure in explosions depend on various conditions including the type of the fuel (Alharbi et al, 2014), the stoichiometry (Alharbi et al, 2014), ignition location (Rocourt et al, 2014) and the configuration of obstruction (Ibrahim et al, 2009;Na et al, 2017), etc. Thus, accurate prediction and assessment of explosion is a challenging task.…”

Section: Introductionmentioning

confidence: 99%

On the mechanism of pressure rise in vented explosions: A numerical study

Malalasekera

Ibrahim

et al. 2018

Process Safety and Environmental Protection

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Accidental gas explosions are a significant concern in process industries. In an explosion event, the promotion of flame acceleration due to turbulence generated from obstacles is responsible for many severe damages. This paper discusses the numerical evaluation and the mechanism of pressure rise in vented explosions in the presence of obstructions using computational fluid dynamics (CFD). The large eddy simulation (LES) technique is employed with a dynamic flame surface density (DFSD) in the combustion model to account for the filtered chemical source term. The experimental test case considered for the validation of simulations is a smallscale explosion chamber with removable baffle plates and obstacles. It is found that the maximum overpressure increases with the baffle plates moved downstream from the ignition source or when additional baffles are placed in sequence. Large separation between baffles and the central obstacle results in lower overpressure due to the relaminarisation of the flame front. The trend of explosion overpressure is related to the competition between the strength of venting and expansion in the explosion chamber. Extensive interactions between the flame and the obstructiongenerated turbulence are found to wrinkle the flame front and increase the burning rate. Satisfactory agreements have been obtained between LES and the experimental data. This confirms the capability of the developed model in predicting essential safety-related parameters in vented explosions. Results reveal the potential of using LES in the selection of design aspects for loss prevention, such as the area of vents and distance between congested regions in chemical processing plants.

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“…The vent area ratio ( V ) is introduced to quantitatively investigate the effect of vent area on the pressure peaks. In this paper, the vent area ratio is defined as V = V / 2/3 [25], where V is the vent area and is the volume of a compressor compartment. The VBR is defined as the volume fraction occupied by compressors inside the compartment, characterizing the degree of obstruction [24].…”

Section: Simulation Conditionsmentioning

confidence: 99%

CFD Simulations to Study Parameters Affecting Gas Explosion Venting in Compressor Compartments

Cen

Song

Huang

et al. 2017

Mathematical Problems in Engineering

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In this work, a series of vented explosions in a typical compressor compartment are simulated using FLACS code to analyze the explosion venting characteristics. The effects of relevant parameters on the pressure peaks (i.e., overpressure and negative pressure) are also numerically investigated, including vent area ratio of the compressor compartment, vent activation pressure, mass per unit area of vent panels, and volume blockage ratio of obstacles. In addition, the orthogonal experiment design and improved grey relational analysis are implemented to evaluate the impact degree of these relevant parameters. The results show that the pressure peaks decrease with the increase of vent area ratio. There is an approximately linearly increasing relationship between the pressure peaks and the vent activation pressure. The pressure peaks increase with the mass per unit area of vent panels. The pressure peaks increase with the volume blockage ratio of obstacles. Based on the grey relational grade values, the effects of these relevant parameters on the overpressure peak are ranked as follows: volume blockage ratio of obstacles > vent activation pressure > vent area ratio > mass per unit area of vent panels. These achievements provide effective guidance for the venting safety design of gas compressor compartments.

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Vented hydrogen–air deflagration in a small enclosed volume

Cited by 109 publications

References 9 publications

Experiments on vented hydrogen-air deflagrations: The influence of hydrogen concentration

Experiments on vented hydrogen-air deflagrations: The influence of hydrogen concentration

On the mechanism of pressure rise in vented explosions: A numerical study

CFD Simulations to Study Parameters Affecting Gas Explosion Venting in Compressor Compartments

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