Developments in modelling of thermal radiation from pool and jet fires

Abstract

In the past decades, the standard approach in the modelling of consequences of pool and jet fires would be to describe these fires as tilted cylindrical shaped radiating flame surfaces, having a specific SEP (Surface Emissive Power). Some fine tuning on pool fires has been done by Rew and Hulbert in the late nineties to divide the flame in a clear and sooty part, and provide some typical-substance dependent-values for SEPclear and SEPsoot. However, this approach still describes the pool-fire as a tilted and cylindrical shaped radiator. Unfortunately, in the world, the typical pool fire dimensions, and consequently the flame shape, are being determined by local circumstances, such as the presence of a semi-rectangular bund around storage tanks. Other pool shape determining examples are ditches, drains or even elevated platforms that restrict the free spreading of a pool and lead to a specific pool shape. Of course the resulting pool surface will not only determine pool burning rate, but also the radiation behaviour. In order to predict the consequences of these real world situation, TNO extended the fire modelling in its consequence calculation software EFFECTS® with a more elaborated radiation calculation, additionally providing the possibility to determine heat load distribution on a receiving object. In case of a pool fire, the expected pool dimensions can be drawn (on top of a topographic map or aerial photo) and potential receiving objects can be defined, such as nearby installations, including typical vulnerability thresholds. This enables the possibility to evaluate potential domino effects of a fire. The same approach is also used for jet fires, now describing the jet as a truly cone shaped radiator, which can be pointed in any direction. The paper will provide a full description of the applied method, including some typical application examples. © Copyright 2016, AIDIC Servizi S.r.l.