Experimental Study on Physical Model of Energy Dissipation and Foam Elimination in
Siphon Well of Coastal Power Plant
Abstract: Coastal nuclear power plants often face the problem of foam generation
caused by air entrainment during water jump energy dissipation downstream of the
siphon well overflow weir. The foam, stabilized by seawater chemical properties, creates
visual pollution and salt spray corrosion. This paper presents a physical model test (scale
ratio 1:16) based on the Froude similarity criterion for the drainage siphon well of a
nuclear power plant Phase I project, systematically studying the hydraulic characteristics
and aeration patterns under different tidal levels and operation conditions. The results
show that at average tidal level, virtually no bubbles enter the drainage culvert; the
average low tidal level is the critical condition where noticeable aeration begins; and
under the 100-year return period low tidal level, aeration further intensifies. A
horizontal deflector bucket installed on the weir face is proposed as an auxiliary foamelimination measure. Three schemes with bucket crest elevations of -5.3 m, -5.9 m, and
-6.9 m were compared. The -5.9 m scheme demonstrates the best overall performance
by guiding the main flow horizontally above the support beams, creating a favorable
flow field structure for bubble floatation and effectively reducing the amount of bubbles
entering the drainage culvert.
Keywords: coastal power plant; siphon well; energy dissipation; foam elimination;
physical model test; deflector bucket; air entrainment
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