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Flooding Criterion for Evaporative Cooling on Horizontal Semi Infinite Solids.


pdf icon Flooding Criterion for Evaporative Cooling on Horizontal Semi Infinite Solids. (341 K)
Lederer, M. A.; diMarzo, M.; Tartarini, P.

NIST GCR 96-687; Paper 17; June 1996.

American Society of Mechanical Engineers (ASME). National Heat Transfer Conference. ASME 31st Proceedings. Volume 4: Interfacial Phenomena; Boiling Heat Transfer; Thermal Hydraulics for Advanced Nuclear Reactions. HTD-Vol. 326. August 3-6, 1996, Houston, TX, American Society of Mechanical Engineers, New York, NY, White, L.; Singer, R. M.; Peterson, F.; Cheung, F. B., Editor(s)(s), 213-217 pp, 1996.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
Telephone: 1-800-553-6847 or 703-605-6000;
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Order number: PB96-202304

Keywords:

water sprays; evaporative cooling; solids; flooding; formulations; sprays; equations; droplets

Abstract:

The evaporative cooling of a sparse spray impacting on a hot solid is investigated to determine the limiting condition associated with the liquid flooding of the solid surface. The flooding condition is identified when the evaporation rate is insufficient to remove the amount of water being deposited on the surface. The flooding criteria is derived as a function of the initial single droplet volume prior to deposition, the Evaporation-Recovery Cycle (ERC) and the area of influence, which describes the region of the solid surface associated with a single droplet cooling effect. These last two quantities, the ERC and the area of influence, are evaluated by integrating previously obtained theoretical and experimental information with selected experimental data obtained in this study. The flooding criteria, while semi-empirical in its derivation, can be generalized to all non-porous solids under a variety of conditions. The spray is sparse and the water droplets are considered of uniform size. Extension to a spray with non-uniform droplet distribution is not considered here.