Expanding Vapor Explosion Research Articles

Natural explosion structures in rocks

We have observed, in a few hydrothermal breccia bodies near Hong Kong, many peculiar natural explosion structures that bear a strong resemblance to the fracturing patterns produced by quarry blasting. The structures, occurring in hydrothermally altered late Mesozoic volcanic and sedimentary rocks, range in size from a few cm to about 80 cm in diameter, and exhibit a central cavity, a crushed zone around the central cavity, and a radial-crack zone like those formed by explosive blasting. A damage boundary marking the outer extent of the radial fractures is sometimes present. Some of the structures are affected by pre-existing cracks, with the damage boundary stretched in the direction of the crack. Results from detailed field measurements of the morphology, geometric characteristics, and orientations of over a hundred such explosion structures show a spherical geometry of the structure. These natural explosion structures probably formed when rapidly ascending superheated fluids reached the boiling curve, which led to depressurization of the fluids and expanding vapor explosions. The formation mechanism and thermodynamic implications are discussed in this paper, which is the first report of such naturally formed vapor explosion structures in rocks.

Transportation of Liquefied Gases: Assessing the Risk of Thermal Damage to Roadside Infrastructure from a Road Tank “Bleve”

An assessment of risk posed by a road transportation of liquefied gases to roadside property is considered. The attention is focussed on an estimation of the probability of thermal damage to a roadside object. Such damage can be caused by a boiling-liquid expanding-vapour explosion (BLEVE) of a road tank. It is suggested to estimate this probability by a combined application of stochastic simulation and deterministic models used to predict a thermal effect of a BLEVE fireball. A development of a fragility function expressing the probability of ignition of the roadside object is discussed. The fragility function is integrated into the simulation-based procedure of an estimation of the thermal damage probability. The approach proposed in this study is illustrated by an example which considers an assessment of thermal damage to a reservoir built in the vicinity of a road used for transportation of liquefied gases.

Fire Setting by Nuclear Explosion: A Revisit and Use in Nonnuclear Applications

Ignition of cellulosic and similar materials by the thermal radiation from the nuclear fireball largely determines the extent of fires resulting from a nuclear explosion in urban, rural, and wildland areas. Since the 1950s and 60s, it has been known and is well demonstrated that the ignition thresholds in materials exposed to the well-characterized thermal pulse of nuclear airbursts are controlled by thermal absorption and heat conduction. Remarkably, a full range of the ignitable materials subject to such exposure has ignition thresholds that can be forecast this way. This revisit of the pertinent technology from the last half of the twentieth century documents its findings in the open literature, some of it for the first time, while showing how it can be applied not only to computer modeling of nuclear fires but also to other nonnuclear pulsed heat releases for the twenty-first century. Beyond its originally intended purpose of forecasting the fire consequences of a nuclear war, the data correlation presented here can be used to examine a variety of threats associated with intense radiant pulses such as those in natural gas pipeline ruptures and in the class of flammable liquid storage accidents known as boiling-liquid expanding-vapor explosions (BLEVEs).

The mystery of the BLEVE

BLEVE (Boiling Liquid, Expanding Vapor Explosion): The explosively rapid vaporization and corresponding release of energy of a liquid, flammable or otherwise, upon its sudden release from containment under greater-than-atmospheric pressure at a temperature above its atmospheric boiling point. A BLEVE is often accompanied by a fireball if the suddenly depressurized liquid is flammable and its release results from vessel failure by an external fire. The energy released during vaporization may contribute to a shock wave.

Thermal Response Analyses of Spherical LPG Storage Tank.

Liquefied petroleum gas (LPG) is a very important fuel and chemical feed stock as well; however, the hydrocarbon has been involved in many major fires and explosions. One of these accidents is boiling-liquid, expanding-vapor explosion (BLEVE). It is a phenomenon that results from the sudden release from confinement of a liquid at a temperature above its atmospheric-pressure boiling point. The sudden decrease in pressure results in the explosive vaporization of a fraction of the liquid and a cloud of vapor and mist with the accompanying blast effects. Most BLEVEs involve flammable liquids, and most BLEVE releases are ignited by a surrounding fire and result in a fireball. The primary objective of this paper is to develop a computer model in order to determine the thermal response of a spherical LPG tank involved in fire engulfment accidents. The assessment of the safety spacing between tanks was also discussed.

Modeling a Boiling-Liquid, Expanding-Vapor Explosion Phenomenon with Application to Relief Device Design for Liquefied Ammonia Storage

This paper addresses a fictitious accident scenario involving an ammonia storage tank in a refinery. Ammonia is used in a deNOx system. In a selective catalytic reduction environment, a refinery stack gas containing nitric oxide and nitrogen dioxide is decomposed into nitrogen and water vapor. In this study, a cylindrical ammonia tank is “bleved” (boiling-liquid, expanding-vapor explosion (BLEVE)) with an external fire. We developed a computer model in order to determine the thermal response of a horizontal ammonia tank involved in fire engulfment accidents. The assessment of the separation distance between tanks and protection measures such as water spray cooling were also discussed. Further, we examined the relief device design and studied the open-system thermal response as well as pressure response effects in the event of a BLEVE for the ammonia tank.

The los alfaques disaster: A boiling-liquid, expanding-vapour explosion

The los alfaques disaster: A boiling-liquid, expanding-vapour explosion