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| Avtorstvo: |
Jana ŠELIH // 1.01 Izvirni znanstveni članek
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| Leto: |
1994 |
| Citat: |
ŠELIH, Jana, SOUSA, Antonio C. M., BREMNER, Theodore W. Moisture and heat
flow in concrete walls exposed to fire. J. eng. mech., Oct. 1994,
vol. 120, no 10, str. 2028-2043. |
| Povzetek: |
Time-dependent distributions for
temperature and moisture content in a concrete wall subjected to fire are
determined by a model of heat and mass transfer in porous media. Free-water
flow, bound-water diffusion, gas-phase flow, water-vapor diffusion, and
thermal energy are accounted for in the model. The governing transient
differential equations are discretized by a control-volume formulation
reported by Patankar in 1980, and solved in time using a fully implicit
scheme. Two different fire exposure curves (namely, standard curve according
to ASTM E-119 and a more realistic curve reported by Ellingwood in 1991) are
employed in the analysis. The assessment of two simplified models, in which
all pore water is assumed to evaporate at 100 oC, is performed by comparing
their predictions to the full analysis. For temperature and saturation, the
time developments predicted by the two simplified models and by the full
analysis present similar trends; however, the simplified models seem to be
appropriate only for very preliminary fire safety analysis, since they tend
to underestimate temperatures
S kombiniranim numeričnim modelom
masnih in toplotnih pretokov, v poroznem materialu smo določili časovno
spremenljive razporeditve temperature in vsebnosti vlage v betonski steni,
ki je na eni strani izpostavljena požaru. Uporabili smo dva poenostavljena
modela, ter njune rezultate primerjali z rezultati celovitega numeričnega
modela, ki temelji na enačbah pretoka proste tekoče vode, difuzije vezane
vode, pretokov plinaste faze in energetski enačbi, ki upošteva fazne prehode
porne vode. Rezultati kažejo, da se lahko poenostavljeni modeli uporabljajo
le za preliminarno požarno analizo, saj so temperature, dobljene s
poenostavljeno simulacijo, prenizke |
| Tipologija: |
1.01 Izvirni znanstveni članek |
| COBISS ID |
118119 Polni zapis iz sistema COBISS |
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Vpisal 2001/08/08 19:56
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