Transient non-equilibrium two-phase flow: reflooding of a vertical flow channel

Thesis/Dissertation · Sun Jan 01 00:00:00 EST 1984

OSTI ID:5045427

Kawaji, M

Reflooding of a hot vertical tube was investigated in connection with the analysis of the loss-of-coolant accidents in light water reactors. A 3.66 m long, 14.3 mm ID thin-walled Inconel tube was initially heated to a high temperature and reflooded by injection of water from bottom at a constant rate. In addition to wall temperature, fluid carryover and pressure drop measurements, a narrow beam gamma densitometer was used to measure void fractions at three different heights of the tube. Flow patterns and quenching behavior were also visualized by reflooding a heated quartz tube. The experiments showed that while the fluid is subcooled near the quench front, thermal and mechanical non-equilibrium effects are important and can enhance wall-to-fluid heat transfer and quench speed. A strong relationship was found between the liquid volume fraction and wall heat flux. An empirical correlation for the rewetting temperature was also developed. Efforts to improve the model predictions were made including the incorporation of a flow transition region and development of a multi-field model of the dispersed flow regime, which treats the motion of drops in different size groups separately. The predictions improved for some but not all experiments possibly due to the lack of constitutive relations for the intra-group mass and momentum transfer terms.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 5045427
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
WATER COOLED REACTORS
LOSS OF COOLANT
LOSS OF FLOW
REACTOR SAFETY
REWETTING
TUBES
TWO-PHASE FLOW
VOID FRACTION
ACCIDENTS
FLUID FLOW
REACTOR ACCIDENTS
REACTORS
SAFETY
220900* - Nuclear Reactor Technology- Reactor Safety
210200 - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled