Pool boiling from downward-facing curved surfaces: Effects of radius of curvature and edge angle
- Univ. of New Mexico, Albuquerque, NM (United States)
Transient pool boiling from downward-facing curved surfaces in water is of interest for assessing the coolability of the lower head of an advanced light water reactor (ALWR) pressure vessel following a core meltdown accident. Here, quenching experiments were performed to investigate the effects of radius of curvature and edge angle on pool boiling from downwards-facing surfaces in saturated power. The experiments employed two, 20-mm-thick copper test sections that had the same diameter (75 mm) but different surface radii (148 and 218.5 mm) and vapor release (or edge) angles (14.68 and 9.88 deg). The effect of surface area on pool boiling was determined by comparing the present results with the results for a copper section that was of the same thickness but had a surface radius of 148 mm and was less than one-half the surface area. The maximum heat flux (q{sub MHF}) was highest at the lowermost position and decreased with increased local inclination on the surface. Both local and surface average q{sub MHF} were representative of quasi-steady-state critical heat flux. The high edge angle reduced vapor accumulation, which enhanced surface coolability and shortened its quenching time. For an edge angle of 9.88 deg, increasing the surface area (or surface radius) insignificantly affected the local q{sub MHF} near the edge of the copper section but lowered it everywhere else by {approximately}10%. For the same surface area, the larger edge angle (or smaller surface radius) increased q{sub MHF} by as much as 40%.
- OSTI ID:
- 264331
- Journal Information:
- Nuclear Technology, Journal Name: Nuclear Technology Journal Issue: 3 Vol. 114; ISSN 0029-5450; ISSN NUTYBB
- Country of Publication:
- United States
- Language:
- English
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