Two-dimensional analysis of conduction-controlled rewetting with precursory cooling. [Rewetting of fuel elements during emergency core cooling]

Journal Article · Sun Aug 01 04:00:00 EDT 1976 · J. Heat Transfer; (United States)

DOI:https://doi.org/10.1115/1.3450568· OSTI ID:7347723

Dua, S S; Tien, C L

This paper presents a two-dimensional analysis of the effect of precursory cooling on conduction-controlled rewetting of a vertical surface, whose initial temperature is higher than the sputtering temperature. Precursory cooling refers to the cooling caused by the droplet-vapor mixture in the region immediately ahead of the wet front, and is described mathematically by two dimensionless constants which characterize its magnitude and the region of influence. The physical model developed to account for precursory cooling consists of an infinitely extended vertical surface with the dry region ahead of the wet front characterized by an exponentially decaying heat flux and the wet region behind the moving film-front associated with a constant heat transfer coefficient. Apart from the two dimensionless constants describing the extent of precursory cooling, the physical problem is characterized by three dimensionless groups: the Peclet number or the dimensionless wetting velocity, the Biot number and a dimensionless temperature. Limiting solutions for large and small Peclet numbers have been obtained utilizing the Wiener-Hopf technique coupled with appropriate kernel substitutions. A semiempirical matching relation is then devised for the entire range of Peclet numbers. Existing experimental data with variable flow rates at atmospheric pressure are very closely correlated by the present model. Finally a comparison is drawn between the one-dimensional limit of the present analysis and the corresponding one-dimensional solution obtained by treating the dry region ahead of the wet front characterized by an exponentially decaying heat transfer coefficient.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 7347723
• Journal Information: J. Heat Transfer; (United States), Journal Name: J. Heat Transfer; (United States) Vol. 98:3; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220900* -- Nuclear Reactor Technology-- Reactor Safety
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
ECCS
ENERGY TRANSFER
ENGINEERED SAFETY SYSTEMS
FUEL ELEMENTS
HEAT TRANSFER
REACTOR COMPONENTS
REACTOR PROTECTION SYSTEMS
REACTORS
REWETTING
THERMAL CONDUCTION
TWO-DIMENSIONAL CALCULATIONS
WATER COOLED REACTORS