Two-phase flow regimes and carry-over in a large-diameter model of a PWR hot leg. Final report
This report describes a series of tests investigating two-phase flow characterization and carryover in a transparent model of a Babcock and Wilson (B and W) Pressurized Water Reactor (PWR) hot leg geometry. This work was performed, inpart, to support the interpretation of results from the Once-Through Integral System (OTIS) and Multi-loop Integral Test (MIST) facilities. Test conditions were selected to cover a wide range of gas and liquid superficial velocities (0.01 m/s < j/sub g/ < 2 m/s, 0 < j/sub l/ < 0.5 m/s) expected to occur in a prototypical reactor geometry during a small break loss of coolant accident (SBLOCA). Tests at high gas superficial velocities (j/sub g/ > 2 m/s) were also performed for comparison with semi-analytical predictions. Tests were conducted in two different test rigs, one with 10.2-cm (4-inch) diameter pipe, and the other with 30.5-cm (12-inch) diameter pipe. Results include average void fraction, amount of water carryover through the U-bend, transient flow rates and pressure histories, and video movies of the two-phase flow phenomena. Results of the 10.2-cm (4-inch) pipe tests show generally good agreement with the Taitel and Dukler (1) flow regime map for vertical pipes. For the 30.5-cm pipe tests, slug flow was not observed. Instead, as the air flow rate was increased, the flow regime progressed from bubbly to churn-type flow with the presence of large bubbles (approximately 15-cm diameter). The results also indicate that flow regimes and collapsed liquid level are more strongly dependent on air superficial velocity than the water superficial velocity and that the amount of water carryover for a given air flow rate is a strong function of collapsed water level (void fraction). Furthermore, the results show that similar thresholds for breakdown in natural circulation flow exist between the 10.2-cm and 30.5-cm pipe tests for gas and liquid superficial velocities expected in a SBLOCA. 20 refs., 24 figs.
- Research Organization:
- Science Applications International Corp., Los Altos, CA (USA)
- OSTI ID:
- 5980647
- Report Number(s):
- EPRI-NP-4530; ON: TI86920257
- Country of Publication:
- United States
- Language:
- English
Similar Records
Interfacial area and two-phase flow structure development measured by a double-sensor probe
Interfacial area and two-phase flow structure development measured by a double-sensor probe
Related Subjects
42 ENGINEERING
PIPES
HEAT TRANSFER
HYDRAULICS
TESTING
TWO-PHASE FLOW
PWR TYPE REACTORS
NATURAL CONVECTION
TEST FACILITIES
VOID FRACTION
CONVECTION
ENERGY TRANSFER
FLUID FLOW
FLUID MECHANICS
MASS TRANSFER
MECHANICS
REACTORS
WATER COOLED REACTORS
WATER MODERATED REACTORS
210200* - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
420400 - Engineering- Heat Transfer & Fluid Flow