Near-field BLEVE overpressure effects: The shock start model

Heymes

2020

Self Cite

The near-field hazards from BLEVE including blast, ground force, drag loading from the rapid liquid phase change and projectiles. There are several correlations available in the literature for the far field blast overpressure from a BLEVE, usually requiring the calculation of the available expansion energy and the application of correction factors. However, there is very little information available for near-field effects and how this is affected by the details of vessel failure. This work presents near-field blast overpressure data and prediction models to fill in this gap. First, experimental measurements of overpressure in the near-field of a small scale cylindrical controlled BLEVE experiments with propane (V = 0.6 L, d =50 mm, L = 300 mm) were performed. Then, this work establishes a prediction model based solely on the vapour phase properties at failure, using shock tube overpressure prediction and spherical shock propagation models. The model predicts well the strongest tests and is conservative with all the others. Scaling the model up to larger scale experimental data from literature shows that it is transposable, proposing a simple physics-based prediction model for BLEVE overpressure.

Section: Discussionmentioning

confidence: 87%

“…This is a theoretical overpressure if the shock forms at the interface between the high and low pressure. In reality the shock does not form there but rather it forms at some distance from the wall and we called this the shock start distance R so (Birk et al, 2018).…”

Section: Analytical Solutionmentioning

confidence: 99%

Analysis of BLEVE overpressure using spherical shock theory

Birk

Heymes

2020

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“…As the vessel failed a jet of vapour was released as described in (Birk et al, 2020). This jet expanded and went sonic just beyond the edge of the failure opening.…”

Section: Resultsmentioning

confidence: 99%

Ground loading from BLEVE through small scale experiments: Experiments and results

Heymes²,

Birk

2021

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The ground force generated by a BLEVE is a hazard that has been seldom studied, even though BLEVE has been source of many research works in the past decades. However, emergency responders have been asking questions the risk and consequences of a BLEVE on a bridge and other critical infrastructures for a while, with no answer so far. Moreover, a tank truck accident in Bologna in August 2018 has shown that bridge collapse may result from such scenario.This paper presents the experimental work done with a small scale apparatus reproducing realistic BLEVE failure with a cylindrical tube. Load cells were placed under the base plate holding the tube to measure the local ground force generated by the explosion. Forces from 10 kN to 55 kN were measured for a 50 mm diameter tube with 300 mm length failing at pressures from 10 to 32 Bar. The ground force signals are interpreted together with the imaging and internal pressure signal. The synchronization between violent boiling, repressurization in the vessel and strong ground force is clear through this comparison. Different ground force signals were observed depending on the fill level and weakened length of the tube. The maximum ground force and impulse vary almost linearly with failure pressure and liquid fill level. It is less clear for the influence of weakened/ opening length of the tube. More data is required to conclude on this parameter influence.

“…Recently Birk (Birk et al 2007) after an analysis of a number of medium scale BLEVE tests have come to the conclusion that in the case of rupture of high pressure vessels only partially filled with liquid propane (fill level in the range 13 to 61%) the shock waves observed in the far field seem rather produced by expansion of the vapor and not by the vaporization of the liquid, which is said to be a too slow process for generating a strong blast. As a consequence, (Birk et al 2018) proposed a blast prediction model based only on the vapor phase gas dynamics which reproduces quite accurately the experimental data. Another concern is the number of pressure peaks caused by a BLEVE.…”

Section: The Boiling Liquid Expanding Vapour Explosion (Bleve)mentioning

confidence: 96%

An experimental study of water BLEVE

Heymes

Lauret

et al. 2020

A boiling liquid expanding vapor explosion (BLEVE) is an explosion caused by a sudden rupture of a vessel containing a pressurized liquid at a temperature above its boiling point. A BLEVE can occur with all types of liquids and is not a particular phenomenon for flammable liquefied gases such as propane or butane. A particular hazard in the hydrocarbon industry is the use of water at temperatures far above their atmospheric boiling point in steam generation systems. Water is present at high pressure (e.g. 7 MPa) and high temperature (e.g. 300°C). At these conditions the water is superheated and in case of an accidental release the water will undergo a rapid vaporization and a BLEVE type explosion can be expected. This hazard is quit wide spread in all refineries, petrochemical plants, etc. but little data can be found in literature about real size water BLEVE experiments. The aim of this work was to perform BLEVE tests thanks to a 14L pressure vessel designed on purpose to produce high pressure water BLEVE (85 bar). An extended set of pressure gauges was set in the vessel to measure the internal phase change pressure dynamics and around the relief rupture disk to capture the blast wave. Temperature of water was also recorded, and a fast camera (Phantom V2512) was used to see the phenomenon. Data show clearly the pressure recovery in the vessel and multiple blast waves around the vessel. Results are discussed to analyse the risk of water BLEVE.