The entrance effect on subcooled boiling in heated channels

Conference · Wed Nov 01 04:00:00 EST 1989 · Transactions of the American Nuclear Society; (United States)

OSTI ID:5421973

Kurul, N; Podowski, M Z ^[1]

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1. Rensselaer Polytechnic Institute, Troy, NY (USA)

One of the major problems in the analysis of diabatic two-phase flows concerns the effect of thermodynamic nonequilibrium between the phases. In particular, this effect applies to forced-convection subcooled boiling in boiling water reactors (BWRs). An approach commonly used to evaluate the void distribution along reactor coolant channels is based on one-dimensional models of combined two-phase flow and boiling heat transfer. In the subcooled boiling region, the rate of phase change is governed mainly by the lateral transport of the vapor phase toward the subcooled liquid; thus, the related processes cannot be mechanistically modeled by one-dimensional, axially dependent models. Consequently, most existing subcooled boiling models are based on experimental correlations for parameters such as the onset of nucleate boiling (ONB) and the net vapor generation rate. This paper presents the results of analysis of subcooled boiling phenomena in the developing flow region of a boiling channel, based on a mechanistic two-dimensional, two-fluid model. The effect of turbulence has been accounted for by a k-{epsilon} model. The PHOENICS code was used to solve the governing mass, momentum, and energy conservation equations in both the nonboiling and boiling regions. The parameters calculated by the model include radially and axially dependent distributions of the local void fraction, temperatures and velocities of both phases, and the axial distribution of wall temperature.

• OSTI ID: 5421973
• Report Number(s): CONF-891103--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 60
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100* -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
BOILING
BWR TYPE REACTORS
COMPUTER CODES
CONVECTION
COOLING
ENERGY TRANSFER
EQUATIONS
FLOW MODELS
FLUID FLOW
FORCED CONVECTION
HEAT TRANSFER
KINETICS
MASS TRANSFER
MATHEMATICAL MODELS
ONE-DIMENSIONAL CALCULATIONS
P CODES
PHASE TRANSFORMATIONS
REACTOR KINETICS
REACTORS
SAHA EQUATION
SUBCOOLED BOILING
SUBCOOLING
TWO-PHASE FLOW
VOID FRACTION
WATER COOLED REACTORS
WATER MODERATED REACTORS