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Overpressure

About: Overpressure is a research topic. Over the lifetime, 3236 publications have been published within this topic receiving 34648 citations.


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Journal ArticleDOI
TL;DR: In this article, a finite difference method has been developed to simulate water flow in a 2D porous medium with boundary conditions specified in terms of pressure and temperature, which is particularly suitable for simulating the coupled mechanical and thermalfluid-dynamical effects at calderas.

16 citations

Journal ArticleDOI
TL;DR: In this paper, the authors established a semi-confined pipe model with a length of 100m and a cross-sectional area of 0.08m and revealed the multiparameter attenuation characteristics of gas explosions.
Abstract: After establishing a semi-confined pipe model with a length of 100 m and a cross-sectional area of 0.08 m × 0.08 m, the multiparameter attenuation characteristics of gas explosions were revealed for fuel volumes of 0.0128 m 3 , 0.0384 m 3 , 0.064 m 3 , and 0.0896 m 3 . The results showed that the maximum overpressure presented a changing trend of decreasing, increasing and decreasing with increasing distance away from the ignition source. The peak overpressure formed by the shock wave, the flame propagation speed, the maximum density, gas velocity, and combustion rate all followed a trend of increasing and decreasing. However, the peak overpressure formed by the sonic compression wave and the maximum temperature decreased gradually as the distance increased. The fuel volume had a distinct effect on the overpressure, density, temperature, gas velocity, and combustion rate of gas explosions. The maximum overpressure, density, temperature, gas velocity, and combustion rate among all of the gauge points increased as the fuel volume increased, and they were almost all linear functions of the fuel volume. The explosion-proof safety distance tended to increase with increasing fuel volume, while the flameproof distance increased linearly. These results can provide theoretical guidance for the disaster relief efforts of the gas explosion in the process industry.

16 citations

Journal ArticleDOI
TL;DR: This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions, using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion.
Abstract: Strong ground motions induce large dynamic stress changes that may disturb the magma chamber of a volcano, thus accelerating the volcanic activity. An underground nuclear explosion test near an active volcano constitutes a direct treat to the volcano. This study examined the dynamic stress changes of the magma chamber of Baekdusan (Changbaishan) that can be induced by hypothetical North Korean nuclear explosions. Seismic waveforms for hypothetical underground nuclear explosions at North Korean test site were calculated by using an empirical Green’s function approach based on a source-spectral model of a nuclear explosion; such a technique is efficient for regions containing poorly constrained velocity structures. The peak ground motions around the volcano were estimated from empirical strong-motion attenuation curves. A hypothetical M7.0 North Korean underground nuclear explosion may produce peak ground accelerations of 0.1684 m/s2 in the horizontal direction and 0.0917 m/s2 in the vertical direction around the volcano, inducing peak dynamic stress change of 67 kPa on the volcano surface and ~120 kPa in the spherical magma chamber. North Korean underground nuclear explosions with magnitudes of 5.0–7.6 may induce overpressure in the magma chamber of several tens to hundreds of kilopascals.

16 citations

Journal ArticleDOI
TL;DR: In this article, a garage LPG explosion incident was studied numerically using Computational Fluid Dynamics software FLame ACceleration Simulation (FLACS), three scenarios of different LPG-air mixture volumes and LPG concentrations were investigated.
Abstract: An explosion while repairing liquefied petroleum gas (LPG) taxis in a garage located at the ground level of an old residential building constructed in Hong Kong was reported in 2015. Part of the building structures was damaged with the owners staying inside killed. The cause of explosion is still under investigation, but the explosion source can be due to leaking of LPG fuel or flammable clean refrigerants with LPG. A taxi has over 0.5 kg of refrigerant HFC134a (R134a) stored in the air-conditioning unit. A pressure rise exceeding 21 kPa (or 0.21 bar) due to explosion from a small amount of LPG would give damages to the building. As firefighters are always exposing themselves to the risk of explosion when they are carrying out rescue operation in a gas-filled environment, the explosion overpressure has to be more reliably estimated for working out protection schemes during operation. This garage LPG explosion incident was studied numerically using Computational Fluid Dynamics software FLame ACceleration Simulation (FLACS). Three scenarios of different LPG-air mixture volumes and LPG concentrations were investigated. Dispersion of LPG was simulated first with an ignition taken at a position at the garage centre. Overpressure and temperature rise were predicted using a fine grid system with 1 657 600 computing cells was employed. Results were compared with numerical predictions using coarse grids of 207 200 cells. Discussion and conclusions were made with reference to the threshold value of 21 kPa in overpressure.

16 citations

01 May 1994
TL;DR: In this article, a simple model comparable to the TNT-equivalent model is derived for a burst spherical vessel filled with a pressurized gas, which consists of a single relationship between the scaled peak overpressure and the scaled distance.
Abstract: This paper deals with blast waves generated by a bursting spherical vessel filled with a pressurized gas. A large number of numerical simulations are performed. From the results of the simulations, a simple model comparable to the TNT-equivalent model is derived. The new blast wave model consists of a single relationship between the scaled peak overpressure and the scaled distance. Moreover, a closed-form expression for the explosion efficiency as function of the initial velocity only is provided.

16 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023263
2022504
2021174
2020173
2019171
2018174