Prediction for vented explosions in chambers with multiple obstacles

Park, Dal Jae; Lee, Young Soon; Green, Anthony Roland

doi:10.1016/j.jhazmat.2007.11.052

Cited by 40 publications

(14 citation statements)

References 14 publications

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“…It can be seen from Figure 10(a) that, within 280 ms, the flame front almost develops toward the refrigerator in a finger shape. e flame front position and propagation speed increase linearly, and the flame presents laminar burning before it propagates toward the refrigerator [31]. erefore, the peak combustion rate is low before reaching the refrigerator, and its arrival time increases linearly.…”

Section: Characteristics Of Overpressure Formation and Flamementioning

confidence: 99%

Effect of Congestion on Flow Field of Vented Natural Gas Explosion in a Kitchen

Pang

Jin

et al. 2021

Advances in Civil Engineering

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The process of gas explosion venting in a typical Chinese civil kitchen was investigated using computational fluid dynamics technology, focusing on the impact of the scale and cross-sectional characteristics of congestion, such as common furniture and electrical appliances, on the explosion flow-field parameters. An asymmetrical distribution of congestion will cause the uneven combustion of explosion flames in the kitchen. The flame will initially spread on one side of the room and then accelerate toward the surrounding areas, thereby increasing the risk of indoor gas explosion. The typical indoor overpressure change process can be divided into five stages, among which Stage V is found to be related to pseudoclosed combustion. Large-scale congestion has an obstructive effect on the explosion flow field, but it changes under certain conditions, while small-scale congestion only acts as a promoter. The flat congestion cross section helps maintain the stability of the flame structure, whereas the continuous and abrupt change of the congestion cross section can induce strong turbulent combustion. The research results provide a theoretical basis for the prevention and control of natural gas explosion hazards in civil kitchens from the perspective of congestion scale and cross-sectional mutation.

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Section: Characteristics Of Overpressure Formation and Flamementioning

confidence: 99%

Effect of Congestion on Flow Field of Vented Natural Gas Explosion in a Kitchen

Pang

Jin

et al. 2021

Advances in Civil Engineering

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“…Combined with practical tunnel projects and design parameters, in computational models, a steel support bar with a section of 100 mm × 100 mm was positioned at intervals of 1 m along the mine tunnel wall, which is same with the real case of most tunnels in coal mines. The presence of a huge number of steel bars may exert an influence on gas explosion in confined spaces, such as tube and tunnel [24,25]. The turbulence is generated at the locations of the supports and this leads to flame acceleration.…”

Section: Coupling Relation Of Air Shock Wave and High-temperature Flowmentioning

confidence: 99%

Coupling Relation Between Air Shockwave and High-Temperature Flow from Explosion of Methane in Air

Zhang

Pang

Liang

2012

Flow Turbulence Combust

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After a methane-in-air explosion in a coal mine tunnel, a secondary explosion of coal dust is prone to happen. The shockwave in the gas explosion produces a coal dust suspension, and the peak temperature band may detonate that suspension. This secondary detonation depends on the space-time relation between the shockwave and the peak temperature band. This paper presents a methodology to estimate the coupling relation between the air shockwave and high-temperature flow from the explosion of methane in air. The commercial software package AutoReaGas was used to carry out the numerical simulation for the explosion processes of methane in air in the tunnel. Based on the numerical simulation and its analysis, the coupling relation between the leading shock wave and high-temperature flow was demonstrated for a methane-in-air explosion in a tunnel. In the near field of the ignition point, the deflagration wave transmits energy by heat, and the temperature load is in the front of the pressure wave. With development of deflagration and deflagrationto-detonation transition, the corresponding mechanism of energy transmission is changed from heat conduction to shock compression, and a precursor pressure wave is formed gradually. The time interval between the precursor pressure wave and high-temperature flow behind the wave increases with distance. Attenuation of the precursor shock wave and high-temperature flow depends on the length of the methane-in-air space in a tunnel. Beyond the methane-in-air space, the quantitative relation of the time interval between the precursor shock wave and high-temperature flow with axial distance from ignition and the length of methane-in-air space was proposed. 2 Flow Turbulence Combust (2012) 89:1-12 Nomenclature x i space coordinate in the directions i T time ρ density U flow velocity P static pressure μ t turbulent viscosity coefficient k turbulent kinetic energy ε dissipation rate of turbulent kinetic energy C μ model constant (C μ = 0.09 m 2 /s) δ ij Kronecher delta E specific internal energy e internal energy per unit mass E energy dissipation rate coefficient of turbulent flow ε turbulent flow dissipation coefficient characteristic C 1 model constants C 2 model constants m f u fuel mass fraction R f u volumetric combustion rate f u turbulent flow dissipation coefficient characteristic for the fuel Ldistance from closed end to some section in a roadway L 0 length occupied by methane/air mixture in a roadway L/L 0 scaled distance t time interval between precursor pressure wave and high-temperature flow T peak temperature of flow S t turbulent burning velocity u t turbulence intensity L t turbulent macroscale S l laminar burning velocity v kinematical viscosity of unburned mixture

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“…It was found that all sgs combustion models were able to reproduce qualitatively the experiments in terms of step of flame acceleration and deceleration around each obstacle, and shape of the propagating flame [20]. The predictive ability between existing models on explosion venting, such as the NFPA, Molkov and Yao equations, were examined against experimental data of peak pressures obtained in various chambers with internal obstacles [21].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Suppression of Methane Explosion Containing Obstacles with Ultra-fine Water Mist

Xue¹,

Li²,

Zhu³

et al. 2014

Fire Saf. Sci.

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The effects of obstacles on methane explosion inside a narrow space and its suppression by ultra-fine water mist are investigated experimentally. Two PCB pressure transducers and two E12-1-C-U fast response thermocouples are used to obtain the explosion pressure and temperature, respectively. A Fastcam Ultima APX high speed video camera is used to visualize the process of methane explosion with the influence of obstacles and ultra-fine water mist. The results show that the explosion would be strengthened by the obstacles, while the further strengthening occurs to the cases where the obstacles are farther from the ignition electrode. In addition, the more the obstacles are, the stronger the explosion strengthening will be. The reinforcement effect on gas explosion of the square ring is a little stronger than the column one. The suppression of methane gas explosion containing obstacles with ultra-fine water mist is very effective. KEYWORDS: gas explosion, explosion overpressure, explosion suppression, water mist

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Prediction for vented explosions in chambers with multiple obstacles

Cited by 40 publications

References 14 publications

Effect of Congestion on Flow Field of Vented Natural Gas Explosion in a Kitchen

Effect of Congestion on Flow Field of Vented Natural Gas Explosion in a Kitchen

Coupling Relation Between Air Shockwave and High-Temperature Flow from Explosion of Methane in Air

Experimental Study on Suppression of Methane Explosion Containing Obstacles with Ultra-fine Water Mist

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