Vent burst pressure effects on vented gas explosion reduced pressure

Fakandu, Bala Mohammed; Andrews, Gordon E.; Phylaktou, Herodotos N.

doi:10.1016/j.jlp.2015.02.005

Cited by 81 publications

(13 citation statements)

References 9 publications

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“…Once the flame exits the vessel this will ignite any vented flammable gas not diluted by the atmosphere in its wake. The external explosion is often more severe than the internal explosion and there are many factors that can contribute to the severity, such as vent size (Bauwens et al, 2010) and vent burst pressure (Fakandu et al, 2015). The internal gas concentration before ignition can have an effect; rich mixtures often result in more severe explosions as there is more fuel available for combustion (Gill et al, 2016) and the opposite is true of lean mixtures.…”

Section: Nomenclature Tmentioning

confidence: 99%

Experimental investigation of potential confined ignition sources for vapour cloud explosions

Gill

Atkinson

Cowpe

et al. 2020

Process Safety and Environmental Protection

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Electrical control boxes are common on high vapour cloud hazard sites, and in the case of the Buncefield explosion the ignition source was inside such a box, that was sited in an emergency pump house building. There has, however, been relatively little previous research into this type of ignition mechanism and its effect on the explosion severity. Commercially available electrical control boxes measuring 600 mm high, 400 mm wide and 250 mm deep were used to explore the pressure development, venting processes and flame characteristics of stoichiometric propane/air explosions using aluminium foil and the supplied doors as vent coverings. In some tests, the boxes were empty in order to establish a baseline for the effect of the internal congestion of the boxes. In other tests a congestion array was added. It was found that, in both the empty and congested box tests, the door produced a flat petal shaped flame, which differed drastically from the mushroom flame shape and associated rolling vortex bubble venting that is traditionally observed with large orifice vented explosions.

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Section: Nomenclature Tmentioning

confidence: 99%

Experimental investigation of potential confined ignition sources for vapour cloud explosions

Gill

Atkinson

Cowpe

et al. 2020

Process Safety and Environmental Protection

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“…Their findings showed that the maximum pressure does not increase monotonically with the vent failure pressure under central and rear ignition. The same vessel was employed by Fakandu et al [4] to investigate the effect of vent burst pressure on the maximum reduced explosion pressure of methane air and ethylene air mixtures. They observed that the dominant peak pressure depends on both the vent burst pressure and the vent coefficient K ( where V is the vessel volume and A v is the vent area).…”

Section: Introductionmentioning

confidence: 99%

The effect of vent burst pressure on a vented hydrogen–air deflagration in a 1 m3 vessel

Rui

Guo

et al. 2018

International Journal of Hydrogen Energy

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A series of experiments are conducted to investigate the effect of vent burst pressure on stoichiometric hydrogen air premixed flame propagation and pressure history in a 1 m 3 rectangular vessel in this paper. Pressure buildup and flame evolution are recorded using piezoelectric pressure transducers and a high-speed camera, respectively. The results show typical pressure peaks of three different mechanisms for all vent burst pressures in the experiments. The first pressure peak, generated by the rupture of the vent cover, increases with the vent failure pressure, with the subsequent outflow inertia of combustion products giving rise to a negative pressure. The second pressure peak results from the constant bulk motion of the flame bubble (the Helmholtz oscillation), and the third is produced by the interaction between the combustion waves and the acoustic waves. The time interval between the first pressure peak and the second pressure transient remained nearly constant. The Helmholtz oscillation always appears as the vent ruptures and its magnitude increases with the vent burst pressure. Furthermore, the lower the vent failure pressure, the longer the Helmholtz oscillation is sustained. The peak of the acoustically enhanced pressure always occurs within several milliseconds of the flame front to nship between the maximum reduced explosion overpressure and the vent burst pressure precisely. Also, it is observed that the maximum lengths of the external flames were found to be nearly identical in all tests, but the average propagation rate of the flame front increases with the vent burst pressure. It is interesting that a phenomenon of intense oscillation of internal flame bubble was observed with the increase of vent burst pressure.

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“…Since early 1970s, numerous analytical models, empirical correlations (Bradley and Mitcheson, 1978;Cooper et al, 1986;Molkov, 1999;Tamanini, 2001) and engineering guidelines (NFPA-68, 2007(NFPA-68, , 2013 have been developed to estimate the vented explosion pressure. More recent studies have also been extensively conducted to better understand the turbulent flame acceleration and combustion inside the chamber (Chao et al, 2011;Fakandu et al, 2015;Tomlin et al, 2015;Bao et al, 2016;Qi et al, 2016) However, compared to the studies on internal pressure of vented explosion, combustion outside the enclosure has received little attention, although it could also be destructive to adjacent/far end structures (Palmer and Tonkin, 1980). The external gas explosion can occur simultaneously or earlier before the flame emerges from the enclosure, which eventually increase the peak pressure (Solberg et al, 1980;Schildknecht and Geiger, 1983).…”

Section: Introductionmentioning

confidence: 99%

Internal and external pressure prediction of vented gas explosion in large rooms by using analytical and CFD methods

Hao

2017

Journal of Loss Prevention in the Process Industries

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This paper presents an analytical and a numerical method to predict the internal and external pressures from vented gas explosion in a large enclosure. The first peak internal pressure near the venting of enclosure, which is the primary factor related to the external pressure in far field, is predicted by using analytical correlations. The accuracy of the analytical method is verified by using data from a series of experiments with idealized conditions. However, the incapability of external pressure prediction and over-prediction of peak internal pressure are seen in the realistic scenario by using the analytical approach. Therefore computational Fluid Dynamics (CFD) simulations are consequently performed to accurately estimate both the internal and external pressures of vented explosions. A CFD modelling procedure is suggested in this paper to model the turbulent flame inside the enclosure by using FLACS and to calculate the blast wave propagation with low turbulence in free air by using ANSYS Fluent. This combined CFD modelling approach is proven yielding good predictions of internal and external pressures from vented explosions.

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Vent burst pressure effects on vented gas explosion reduced pressure

Cited by 81 publications

References 9 publications

Experimental investigation of potential confined ignition sources for vapour cloud explosions

Experimental investigation of potential confined ignition sources for vapour cloud explosions

The effect of vent burst pressure on a vented hydrogen–air deflagration in a 1 m3 vessel

Internal and external pressure prediction of vented gas explosion in large rooms by using analytical and CFD methods

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