A CFD and Experimental Investigation of the Mixing Process in Compartment Fires

Guigay, G.; Most, J.; ElÃ-asson, J.; Karlsson, B.

doi:10.3801/iafss.fss.10-1043

Cited by 3 publications

(7 citation statements)

References 11 publications

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“…The velocity profiles for the hot layer at the opening were studied in detail at different time steps [1]. Fleischmann et al [4] first observed a particular shape of the velocity profile.…”

Section: Quantitative Resultsmentioning

confidence: 99%

“…The detailed description of the apparatus, control variables and experimental procedure can be found in Ref. [1].…”

Section: Description Of the Experimentsmentioning

confidence: 99%

“…FDS-B-T100 stands for the FDS run in bottom configuration and T h = 100 °C. A complete description of the model is given [1], where its advantages and disadvantages are also discussed.…”

Section: Description Of the Fds Numerical Modelmentioning

confidence: 99%

“…The same study is done for the bottom configuration, detailed in Ref. [1]. The dominant source of mixing depends on the opening configuration.…”

Section: Quantification Of the Mixingmentioning

confidence: 99%

“…The work presented in this article is part of a PhD thesis called "CFD and experimental investigation of under-ventilated compartment fires" [1]. Its objective was to obtain a better understanding of gravity currents [2][3][4][5] and the resulting mixing in a fire enclosure.…”

Section: Introductionmentioning

confidence: 99%

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A CFD and Experimental Investigation of the Mixing Process in Compartment Fires

Guigay¹,

Eliasson²,

Karlsson³

2011

Fire Safety Science - Proceedings of the 10th International Sym

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The mixing of reactants, hot fuel-rich gas and cold air, by a gravity wave, is a complex hydrodynamic process essential in the initiation of hazardous conditions in an under-ventilated compartment fire. The mixing process is first studied by carrying out experiments on a specific enclosure, characterizing the gravity wave by means of particle image velocimetry measurements and fast tomography visualizations. The results are then used to calibrate and validate numerical and CFD models of these experiments. Both numerical and experimental methods permit to determine complex hydrodynamic processes such as Kelvin-Helmholtz instabilities and Van Karman vortices, and to quantify the mixing level in a fire compartment.

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“…The velocity profiles for the hot layer at the opening were studied in detail at different time steps [1]. Fleischmann et al [4] first observed a particular shape of the velocity profile.…”

Section: Quantitative Resultsmentioning

confidence: 99%

“…The detailed description of the apparatus, control variables and experimental procedure can be found in Ref. [1].…”

Section: Description Of the Experimentsmentioning

confidence: 99%

“…FDS-B-T100 stands for the FDS run in bottom configuration and T h = 100 °C. A complete description of the model is given [1], where its advantages and disadvantages are also discussed.…”

Section: Description Of the Fds Numerical Modelmentioning

confidence: 99%

“…The same study is done for the bottom configuration, detailed in Ref. [1]. The dominant source of mixing depends on the opening configuration.…”

Section: Quantification Of the Mixingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A CFD and Experimental Investigation of the Mixing Process in Compartment Fires

Guigay¹,

Eliasson²,

Karlsson³

2011

Fire Safety Science - Proceedings of the 10th International Sym

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A Different Approach to Vent Flow Calculations in Fire Compartments using the Critical Flow Condition

Guigay

Eliasson

Karlsson

et al. 2010

Journal of Fire Sciences

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In enclosure fires, density-driven vent flow through an opening to the fire compartment is directly dependent on the state of the fire and the evacuation of smoke and hot gases. If a fire is strongly under-ventilated, there may be heavy production of flammable gases. If a sudden opening occurs, e.g., a window breaks or a fireman opens a door to the fire compartment, fresh air enters the compartment and mixes with hot gases, thus creating a flammable mixture that might ignite and create a backdraft. In this article, we consider the critical flow approach to solve the classical hydraulic equations of density-driven flows in order to determine the gravity controlled inflow in a shipping container full of hot unburnt gases. One-third of the container's height is covered by the horizontal opening. For the initial condition, i.e., just before opening the hatch, zero velocity is prescribed everywhere. When the hatch is opened, the incoming air flows down to the container floor and the hot gas flows out. The interface in between them (the neutral plane) can move up like a free surface in internal flows, making it possible to use the techniques of open channel hydraulics devised by Pedersen [1].In this article the critical flow condition, known from classical hydraulics, is used providing a new equation for the vent flow problem. Two flow correction coefficients are considered at the opening, taking into account the uneven distribution of velocity (a) and the effect of mixing and entrainment (C). The value of these coefficients is evaluated using computational fluid dynamics simulations and physical model results performed for the same geometry. Together, these two coefficients form the flow correction coefficient used in practical formulas for vent flow in fire protection engineering. These are known to have a little different values for different geometries and flow situations. The resulting flow coefficient varies slowly with the density difference, shows a small variation with geometry and compares well with previously published data.

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A Numerical Study on Fire Development in a Confined Space Leading to Backdraft Phenomenon

Król

Krawiec

2020

Energies

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This paper presents the results of numerical experiments on fire development and the backdraft phenomenon. The numerical model of fire development built with the use of Ansys Fluent was then validated based on literature data taken from real fire experiments. Some theoretical foundations of airflow and combustion modelling were added. Some features of the numerical model, which allowed for its high accuracy to be achieved, were widely discussed. Since large buoyancy forces were involved, to reproduce the decrease of the atmospheric pressure with height, a variable static pressure was applied using UDF (user-defined function).The results showed good accordance taking into account both the temperature profiles and the distribution of the airflow velocity. Once the model was validated, the research was extended to examine the backdraft phenomenon. The results revealed characteristic phases of the phenomenon and the occurrence of the gravity current as well, which were reported by empirical experiments.

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A CFD and Experimental Investigation of the Mixing Process in Compartment Fires

Cited by 3 publications

References 11 publications

A CFD and Experimental Investigation of the Mixing Process in Compartment Fires

A CFD and Experimental Investigation of the Mixing Process in Compartment Fires

A Different Approach to Vent Flow Calculations in Fire Compartments using the Critical Flow Condition

A Numerical Study on Fire Development in a Confined Space Leading to Backdraft Phenomenon

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