Explosion risks are generally involved with the potential explosive atmosphere. It can occur during storage, transportation or processing of flammable substances (liquid, gases or solid). There are variety of explosions. We concentrate mainly on Gas (Vapor Cloud) explosion, Boiling Liquid Expanding Vapor Explosion (BLEVE), Underground gas pipeline explosion and Explosive substances.
Gas explosions/Vapor cloud explosions: Normally, when a flammable gas-air (oxygen) mixture accumulates and comes into contact of an ignition source a gas (vapor cloud) explosion occurs. Depending on the congestion and confinement present on the site the over pressure may reach to unexpected levels (~ 20 bar). Hence, proper explosion loads on structure are required to be carefully assessed. Doing so requires the estimation of total flammable volume that can contribute towards explosion. Experiments may not be possible to construct for real scenarios. Therefore, validated CFD code like FLACS can provide better picture of explosion/mechanical loading on the components present in the vicinity.
BLEVEs: Such events are possible when a closed container fail to sustain the pressure produced by vaporized fluid. A chemical or physical explosion wil be the result depending on fluid type. After explosion a fireball evolves. Explosion over pressure and fireball thermal radiation can be disastrous to the mankind and nearby infrastructure. One of such experiment and CFD model prediction are shown for an organic peroxide in Fig. 1.
Explosives: Explosives generate wide range of over pressures (depending on the detonation speed, Mach number and shock strength) that can be estimated with relevant experiments and equations. Normally, TNT (Tri Nitro Toluene) explosion data are used as benchmark to compare the strength of a particular explosion (Fig. 2).
Underground gas pipeline explosion: A crater forms when an underground explosion occurs (Fig. 4). The characteristics of crater can provide crucial information on total explosive quantity (TNT equivalent) and hence source over-pressure and safety distances. CFD models are utilized in our group to predict the crater shape and size successfully as shown in Fig. 5 In the recent past Gas pipelines passing through the populated areas underwent explosions and fire . They are potential threat to the residents and infrastructure. Thus, all possible ways should be utilized to prevent any disaster. We have developed computational models to estimate reliable safety distances from worst-case events with pipelines.
~striving for a safer tomorrow~
TECHNOLOGICAL RISK RESEARCH & ANALYSIS GROUP (TRAG)
तकनीकी जोखिम अनुसंधान एवं विश्लेषण समूह (ट्राग)