Topic
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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TL;DR: In this paper, the authors used brightness subtraction to eliminate the background effects for obtaining accurate time evolution records of flame propagation velocity, and a new blast curve plot of scaled overpressure vs. distance was tentatively proposed.
Abstract: Deflagration phenomena in hydrogen–air mixtures initially filled in 1.4 m 3 spherical latex balloons were measured using a high-speed digital video camera and pressure transducers. The image velocimetry using brightness subtraction was introduced to eliminate the background effects for obtaining accurate time evolution records of flame propagation velocity. The maximum flame propagation velocity of about 100 m/s was observed with maximum overpressure 15 kPa at 1 m from ignition point. According to the detailed flame propagation velocity records, there were long deceleration durations. The observed maximum overpressure was smaller than the overpressure estimated by the basis of the observed maximum flame propagation velocity and the pressure wave theories of spherical flames. A new blast curve plot of scaled overpressure vs. distance was tentatively proposed.
32 citations
TL;DR: In this article, a detailed numerical model was developed in the commercial software AUTODYN, which showed a good agreement with the test data, and an applicable blast loading model under close-in explosion induced by the double-end-in-initiation explosive cylinder considering D/L ratio and scaled distance was finally established based on test data and numerical calculations.
32 citations
TL;DR: In this article, a water mist containing a NaCl additive charged by induction charging was used to inhibit a methane explosion in a small experimental pipeline, and the experimental results show that the inhibition of the methane explosion overpressure using the water mist consisting of only NaCl was significantly enhanced after the water mixture was charged.
32 citations
TL;DR: In this article, the authors describe a project in which the behavior of coal dust and toner dust explosions in systems of linked enclosed vessels has been studied, and a simple method for the calculation of explosion pressure enhancement effects is described.
Abstract: Some industrial dust-handling plant is designed so that, should an explosion occur, the overpressures can be totally contained. Such plant needs to be designed to withstand at least 10 bar overpressure. This may suffice for single compact vessels but experience indicates that in interconnected plant, explosion overpressures can be substantially increased. This effect is due to a process known as pressure-piling. There is no adequate guidance on how to take the effects of this process into account. This paper describes a project in which the behaviour of dust explosions in systems of linked enclosed vessels has been studied. Explosions of coal dust and toner dust have been produced in a number of linked systems using vessels ranging in size from 2 to 20 m3 and connected by 5 m lengths of pipe with diameters of 0.15 m, 0.25 m and 0.5 m. Pressure changes that occur when a dust explosion is ignited in one of the vessels and the flame transmits into the other have been measured. Pressure enhancement due to pressurepiling effects occurs in some systems, and pressures approaching 20 bar have been measured. The pipe diameter, vessel volumes and the volume ratio are important variables. These results are discussed and a simple method for the calculation of explosion pressure enhancement effects is described. Comparisons are made between the model predictions of the maximum explosion pressure and experimental measurements. The experiments have shown that, in some circumstances, there is a low probability of an explosion propagating along the pipe to produce an explosion in the second vessel. It appears that although the flame travels through the pipe and a jet flame enters the second vessel, it does not act as an effective ignition source. The wider the pipe diameter, the higher the frequency of an explosion in the second vessel.
32 citations
TL;DR: In this paper, an experimental system of explosion of mixed gas-coal and dust in a straight pipe was established in a laboratory, and the evolution of overpressure and the flame-propagation law of coal-dust explosion with different moisture contents were then studied.
32 citations