Interaction analysis of turbulent natural convection and radiation in compartment fires
A computational study has been performed on interactions of turbulent natural convection and radiation in the pre-flashover compartment fire. The development two-dimensional mathematical model is based on differential field equations for conservation of mass, momentum and energy. Radiation through gas-soot mixtures was analyzed by the P{sub 1} differential approximation method with the weighted-sum-of-gray-gases model. Together with a k-{epsilon} model for turbulent flows, the Favre (mass) averaged formulation possesses compatibility in the equation forms which can be efficiently solved by an iterative method incorporating a multi-dimensional simultaneous algebraic equations solver. A test problem solved by the developed model was laminar and turbulent natural convection-radiation interactions in the differentially heated square enclosure filled with carbon dioxide gas. Predictions were in good agreement with data available in the literature and the measurement conducted as part of the present research by holographic interferometry. A heat transfer correlation was obtained for the turbulent natural convection regime (10{sup 7} {le} Gr.Pr {le} 10{sup 10}) with the surface/gas radiation mode (150 {le} Bo {le} 300) as Nu = 0.343(Gr.Pr){sup 0.307} Bo{sup 0.151} where Bo is the Boltzmann number (interaction parameter). A compartment fire analysis was performed on a room-corridor system with a localized fire source in the room. Layered structures were observed in the vertical direction of flow and temperature fields. Gas/soot radiation assisted forming more prominent layered structures. The validity of the two-dimensional model as an idealization of a three-dimensional model has been verified with three-dimensional computations and a measurement.
- Research Organization:
- Drexel Univ., Philadelphia, PA (USA)
- OSTI ID:
- 6376944
- Country of Publication:
- United States
- Language:
- English
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CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
COMPARTMENTS
CONVECTION
DISPERSIONS
ENERGY TRANSFER
EQUATIONS
FIRES
FLOW MODELS
FLUID FLOW
FLUIDS
GASES
HEAT TRANSFER
HOLOGRAPHY
INTERFEROMETRY
LAMINAR FLOW
LAYERS
MASS
MASS TRANSFER
MATHEMATICAL MODELS
MIXTURES
NATURAL CONVECTION
OXIDES
OXYGEN COMPOUNDS
RADIANT HEAT TRANSFER
SOOT
TEMPERATURE DISTRIBUTION
TESTING
THREE-DIMENSIONAL CALCULATIONS
TURBULENT FLOW
TWO-DIMENSIONAL CALCULATIONS
VALIDATION