Transient heating of a thermally thin vertical solid slab in air by a constant uniform radiant flux
The history of heating of a thermally thin vertical solid exposed to a uniform and constant radiant flux on one face is studied in this paper. The transient development of free convective boundary layer and reradiation from the solid surface are included in the model. Among the interesting findings are: the boundary layer growth process exhibits an 'overshoot' before reaching a steady state; the free convective Nusselt number exhibits a corresponding undershoot; reradiation plays a significant role only if the reradiant Biot number is large; the transient heat transfer results can be represented on a Nu(Gr) plot in which Galileo number is a parameter; and, based on a prescribed critical temperature enterion, the threshold exposure intensity below which ignition is impossible can be predicted. The need is pointed out for future consideration of pyrolysis of the heated solid, mixing of the fuel vapors with air in the transient boundary layer, and simultaneous fulfillment of thermal and composition conditions suitable for ignition in the boundary layer.
- Research Organization:
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana
- OSTI ID:
- 5339561
- Report Number(s):
- CONF-830702-
- Journal Information:
- HTD (Publ.) (Am. Soc. Mech. Eng.); (United States), Journal Name: HTD (Publ.) (Am. Soc. Mech. Eng.); (United States) Vol. HTD-VOL. 25; ISSN ASMHD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420400* -- Engineering-- Heat Transfer & Fluid Flow
AIR
BOUNDARY LAYERS
CHEMICAL REACTIONS
CONVECTION
DECOMPOSITION
ENERGY TRANSFER
FLUIDS
FLUX DENSITY
FUELS
GASES
HEAT TRANSFER
HEATING
IGNITION
LAYERS
MIXING
NATURAL CONVECTION
NUSSELT NUMBER
PYROLYSIS
RADIANT FLUX DENSITY
RADIANT HEAT TRANSFER
SLABS
SOLIDS
STEADY-STATE CONDITIONS
THERMOCHEMICAL PROCESSES
TRANSIENTS
VAPORS