Systematic and exact scaling analysis of the single-phase natural circulation flow: The hydraulic similarity

The two-phase natural circulation cooling performance of the APR1400 core catcher system is studied utilizing a drift flux flow model developed via scaling analysis and with an air-water experimental facility. Scaling analysis was carried out to identify key parameters, so that model facility could simulates two-phase natural circulation. In the experimental apparatus, instead of steam, air is injected into the top wall of the test channel to simulate bubble formation and void distribution due to boiling water in the core catcher channel. Measurement of void fraction critical to the heat transfer between the wall and coolant is carried out at certain key position using double-sensor conductivity probes. Results from the model provide expected natural circulation flow rate in the cooling channel of the core catcher system. The observed flow regimes and the data on void fraction are presented. For a given design of the down comer piping entrance condition bubble entrainment was observed that significantly reduced the natural circulation flow rate.

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Unsteady Single-Phase Natural Circulation Flow Mixing Prediction Using CATHARE Three-Dimensional Capabilities

Nuclear Engineering and Technology ◽

10.1016/j.net.2016.11.006 ◽

2017 ◽

Vol 49 (3) ◽

pp. 466-475 ◽

Cited By ~ 2

Author(s):

Anis Bousbia Salah ◽

Jacques Vlassenbroeck

Keyword(s):

Single Phase ◽

Natural Circulation ◽

Three Dimensional ◽

Circulation Flow ◽

Flow Mixing

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Experimental and theoretical study on single-phase natural circulation flow and heat transfer under rolling motion condition

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2009.04.019 ◽

2009 ◽

Vol 29 (14-15) ◽

pp. 3160-3168 ◽

Cited By ~ 106

Author(s):

Si-chao Tan ◽

G.H. Su ◽

Pu-zhen Gao

Keyword(s):

Heat Transfer ◽

Single Phase ◽

Theoretical Study ◽

Natural Circulation ◽

Rolling Motion ◽

Circulation Flow ◽

Flow And Heat Transfer ◽

Motion Condition

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Study of Two-Phase Natural Circulation Cooling of Core Catcher System Using Scaled Model

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4030249 ◽

2015 ◽

Vol 7 (3) ◽

Cited By ~ 1

Author(s):

Shripad T. Revankar ◽

Kiwon Song ◽

B. W. Rhee ◽

R. J. Park ◽

K. S. Ha ◽

...

Keyword(s):

Pressure Drop ◽

Void Fraction ◽

Natural Circulation ◽

Rectangular Channel ◽

Water System ◽

Scaling Analysis ◽

Circulation Flow ◽

Two Phase ◽

Decay Heat ◽

Core Catcher

A two-phase natural circulation cooling has been proposed to remove melted core decay heat by external core catcher cooling system during sever accident scenario. In this paper, two types of the core catcher cooling loops, one with heated loop and the other adiabatic loop simulated with air water system are analytically studied. First, a scaling analysis was carried out for natural circulation flow in a closed loop. Based on the scaling analyses, simulation of two-phase natural circulation is carried out both for air–water and steam–water system in an inclined rectangular channel. The heat flux corresponding to the decay heat is simulated with steam generation rate or air flux into the test section to produce equivalent flow quality and void fraction. Design calculations were carried out for typical core catcher design to estimate the expected natural circulation rates. The natural circulation flow rate and two-phase pressure drop were obtained for different heat inputs or equivalent air injection rates expressed as void fraction for a select downcomer pipe size. These results can be used to scale a steam water system using scaling consideration presented. The results indicate that the air–water and steam water system show similar flow and pressure drop behavior.

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