Iskandar Zulkarnain - Academia.edu (original) (raw)

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Papers by Iskandar Zulkarnain

In the past decades, the standard approach in the modelling of consequences of pool and jet fires... more 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 SEP clear and SEP soot. However, this approach still describes the pool-fire as a tilted and cylindrical shaped radiator. Unfortunately, in the real 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 1. Fire modelling Fire modelling should be seen as an important part of consequence modelling, allowing to predict potential damage due to heat radiation of fires. Fire models themselves can be separated in models describing either jet fire, pool fire or fireball (BLEVE) phenomena. A jet fire model describes the fire phenomenon of a gaseous or two phase (e.g. Propane) continuous release. Such a jet fire model (sometimes referred to as " torch fire ") generally describes the size and shape of a cone or cylindrical shaped fire surface, and provides information about heat radiation versus distance or location. A high outflow velocity will also introduce a lift-off effect, causing the flame shape to start at certain distance from the actual release point. The flame tilt angle of the jet is highly influenced by the wind speed and will thus determine the resulting flame geometry and radiation pattern. A pool fire describes a flame surface on top of a burning liquid pool. The pool fire is usually described as a cylindrical shaped flame geometry, which will be tilted by the wind. Typical results of a pool fire model contain flame diameter, flame height and tilt, and heat radiation levels at various distances from the pool. Although a BLEVE (Boiling Liquid Expanding Vapour Explosion) is technically a description of an explosion (e.g. overpressure) phenomenon, the potential BLEVE of an LPG vessel is feared the most because of its fireball result. Dedicated BLEVE fireball models have been developed, describing the diameter and lift-off a the spherical flame and resulting heat load. These models all have in common that they use " Solid flame modelling " , describing the surface of the flame as a specific geometry, with a typical Surface Emissive Power (SEP) leading to a corresponding heat radiation footprint.

In the past decades, the standard approach in the modelling of consequences of pool and jet fires... more 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 SEP clear and SEP soot. However, this approach still describes the pool-fire as a tilted and cylindrical shaped radiator. Unfortunately, in the real 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 1. Fire modelling Fire modelling should be seen as an important part of consequence modelling, allowing to predict potential damage due to heat radiation of fires. Fire models themselves can be separated in models describing either jet fire, pool fire or fireball (BLEVE) phenomena. A jet fire model describes the fire phenomenon of a gaseous or two phase (e.g. Propane) continuous release. Such a jet fire model (sometimes referred to as " torch fire ") generally describes the size and shape of a cone or cylindrical shaped fire surface, and provides information about heat radiation versus distance or location. A high outflow velocity will also introduce a lift-off effect, causing the flame shape to start at certain distance from the actual release point. The flame tilt angle of the jet is highly influenced by the wind speed and will thus determine the resulting flame geometry and radiation pattern. A pool fire describes a flame surface on top of a burning liquid pool. The pool fire is usually described as a cylindrical shaped flame geometry, which will be tilted by the wind. Typical results of a pool fire model contain flame diameter, flame height and tilt, and heat radiation levels at various distances from the pool. Although a BLEVE (Boiling Liquid Expanding Vapour Explosion) is technically a description of an explosion (e.g. overpressure) phenomenon, the potential BLEVE of an LPG vessel is feared the most because of its fireball result. Dedicated BLEVE fireball models have been developed, describing the diameter and lift-off a the spherical flame and resulting heat load. These models all have in common that they use " Solid flame modelling " , describing the surface of the flame as a specific geometry, with a typical Surface Emissive Power (SEP) leading to a corresponding heat radiation footprint.