Engineering relations for fire plumes

Heskestad, Gunnar

doi:10.1016/0379-7112(84)90005-5

Cited by 269 publications

(167 citation statements)

References 4 publications

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“…where, f m  is the mass flow rate of plume, as shown in the Figure 1, which is the smoke induced solely by a fire (to make a distinction to the increase of smoke due to the entrained fresh air induced by mechanical smoke exhausting) and can be estimated by the plume entrainment models in literatures [14][15][16]. Under an ideal smoke controlling condition, a m  and p m  should be zero, and e m  should equal to f m  .…”

Section: Theoretically Analysismentioning

confidence: 99%

Experimental investigation on influence of smoke venting velocity and vent height on mechanical smoke exhaust efficiency

Wang

et al. 2010

Journal of Hazardous Materials

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Abstract:A set of burning experiments were conducted to investigate the influence of smoke vent height and exhausting velocity on mechanical smoke exhausting efficiency.Results have shown that the smoke exhausting process becomes more efficient due to the increased smoke vent height and the decreased exhausting velocity, which eliminate the plug-holing issue with fewer disturbances on the smoke layer interface.For each certain exhausting velocity, there is a critical value of distance between the vent and the bottom of the smoke layer. When the distance is less than the critical value, the smoke exhausting is inefficient, and the efficiency decreases sharply as the distance decreases. Contrarily, when the distance is greater than the critical value, a good efficiency can be acquired and the exhausted smoke increased relatively slowly as the distance increases. A critical Froude number, proposed by Hinkley to predict the onset of plug-holing effect in gravity venting systems, was validated in the experiments. However, the experimental results indicate that in the tests without the plug-holing, the fresh air entrained due to smoke exhausting is up to 48% of the mechanical exhausting rate.

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Section: Theoretically Analysismentioning

confidence: 99%

Experimental investigation on influence of smoke venting velocity and vent height on mechanical smoke exhaust efficiency

Wang

et al. 2010

Journal of Hazardous Materials

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“…[1,2,8,10,11,12]. These models are restricted to particular types of fires (area sources or line fires).…”

Section: Flame Entrainmentmentioning

confidence: 99%

Flame Entrainment and Its Application to Compartment Fires

Lattimer¹

2008

Fire Saf. Sci.

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Entrainment into flames is important in predicting the mass flow into the upper-layer of compartment fires where the flame height is similar to or greater than the layer interface height. An analytical model for entrainment into flames was developed based on the simple wetted perimeter approach. The model was validated with existing data and other analytical models for area and line fires located in the open, against a wall, and in a corner. The validated flame entrainment model was integrated into a two-layer compartment fire model and used to predict door flow rates and interface heights with the fire in different locations within the compartment. Predicted door flow rates and interface heights agreed well with compartment fire data from several sources.

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“…There is no effect on this free entrainment of air by walls or other objects. The relationships for air entrainment into the fire plume used by FPETool were developed by Heskestad [11]. Heskestad's relationships deal with axisymmetric, turbulent fire plumes in which the environment is uncontaminated by fire products and is uniform in temperature.…”

Section: Fire Plume Algorithmmentioning

confidence: 99%

“…This limiting elevation , is defined as the elevation within the plume where the mean center line temperature increase = 500 EC (900 EF). For normal atmospheric conditions, the limiting elevation can be expressed as [11]:…”

Section: Fire Plume Algorithmmentioning

confidence: 99%

“…The relationship becomes inaccurate for fire sources with substantial in-depth combustion such as well ventilated wood crib and wood pallet fires, fires involving high storage, and vertical wall or corner fires [11]. A fire with substantial in-depth combustion may have a large portion, greater than 33%, of the volatiles undergoing combustion within or internally of the fuel array by air entering the array [13].…”

Section: Fire Plume Algorithmmentioning

confidence: 99%

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