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Fuel Fire and Explosion

BlazeTech has developed a number of fire and explosion models over the years including:

Also, the above modules can be coupled together to model domino effects.

PoolFire

PoolFirePic image

When a liquid phase fuel is released from a storage tank, it forms a pool on the ground. In the presence of an ignition source, this pool ignites and forms a pool fire. Heat is released from pool fires due to fuel combustion. A number of heat transfer processes are kicked off including heat transfer from ground to the liquid in the pool and radiation heat transfer from the fire to the pool. These processes are accounted in our PoolFire model.

PoolFire Model Inputs

PoolFire Outputs

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BLEVE

Under rapid heating (for example, from a pool fire engulfing the tank), a tank containing pressurized liquid may fail suddenly producing an explosive effect. The liquid in the tank absorbs energy from the surrounding fire and heats up rapidly. The resulting increased rate of vaporization produced increases the ullage pressure. When this pressure exceeds a certain limit (characteristic of the material properties of the tank wall, wall thickness and temperature), the tank fails. The liquid released from the tank boils rapidly and expands. The resulting explosion may fragment the tank into pieces and propel them over large distances. If the hazmat is flammable, it may ignite and form a fireball posing additional hazard. This phenomenon is called a BLEVE or Boiling Liquid Expanding Vapor Explosion.

BLEVE accounts for the following key coupled processes:

Model Inputs

Model Outputs

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Unconfined Vapor Cloud Explosions

We compiled the TNT yields reported for major historical explosions involving accidentally-released fuels.  To interpret the large scatter in the data, we delineated two factors:  the fraction of chemical energy released in the explosion and the fraction of released energy transmitted to the blast.  The latter factor varied little and placed a theoretical upper limit on yield (consistent with the data).  The former was very accident-specific and explained the data scatter. 

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LNG Pool and Vapor Fires

For the Coast Guard, we participated in the design of large spill tests of liquefied natural gas fires (10,000 gallons).  Both pool and vapor cloud fires were produced.  We calculated the flame emissive power based on measurements of flame shapes, sizes and spectral and total radiation fields.  Also, we identified and interpreted new, salient features of the dynamics of vapor cloud fires.  This study formed the basis of state-of-the-art fire models in these areas, which we have tailored and applied to a variety of fuels.

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Oil Well Fires

For the Defense Threat Reduction Agency (DTRA), we have recently developed a model for the prediction of flame temperature, buoyancy flux and emissions from oil well fires. 

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Ignition Sources

For the Gas Research Institute, we conducted a survey of potential devices in a city that might ignite accidentally released vapor clouds of natural gas.  Tests were conducted on the most likely devices such as cigarettes, traffic lights, automobiles, door-bell relays, street lights, etc.  The results were converted into a probability of vapor cloud ignition.

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Petrochemical Fires and Explosions

For several petrochemical plants, we modeled a variety of accident scenarios, including the venting of gases, spills of liquids, and two-phase flow releases.  These releases may be followed by the formation of pool, trench or vapor cloud fires or by fireballs, BLEVEs, and explosions.  In the case of fire, we calculated the thermal radiation field around the fire to estimate the hazard zones for burn injury or wood ignition.  In the case of explosion, we calculated the pressure field around the explosion point to estimate the hazard zones using damage criteria for building collapse, ear drum rupture, window breakage, etc.

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