Numerical analysis on the turbulent natural convection in a long pipeline with thermal stratification

Conference · Mon Dec 01 04:00:00 EST 1997

OSTI ID:552130

Ahn, Jang-Sun; Yune, Seok-Jeong; Ko, Yong-Sang ^[1]

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1. Korea Power Engineering Company, Inc., Taejon (Korea, Republic of); and others

Numerical analysis was performed for the two-dimensional turbulent natural convection for a long horizontal line with different end temperatures. The turbulent model has been applied to a standard k-{epsilon} two equation model of turbulence similar to that proposed by the Launder and Spalding. The dimensionless governing equations are solved by using SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithm which is developed using control volumes and staggered grids. The numerical results are verified by comparison with the operating PWR test data. The analysis focuses on the effects of variation of the heat transfer rates at the pipe surface, the thermal conductivities of the pipe material and the thickness of the pipe wall on the thermal stratification. The results show that the heat transfer rate at the pipe surface is the controlling parameter for mitigating of thermal stratification in the long horizontal pipe. A significant reduction and disappearance of the thermal stratification phenomenon is observed at the Biot number of 4.82x10{sup -1}. The results also show that the increment of the thermal conductivity and thickness of the wall weakens a little the thermal stratification and the thermal conductivity and thickness of the wall weakens a little the thermal stratification and somewhat reduces azimuthal temperature gradient in the pipe wall. These effects are however minor, when compared with those due to the variation of the heat transfer rates at the surface of the pipe wall. 15 refs., 7 figs., 2 tabs.

• Research Organization: American Nuclear Society, La Grange Park, IL (United States)
• OSTI ID: 552130
• Report Number(s): CONF-970607--Vol.2
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
NATURAL CONVECTION
PIPES
PWR TYPE REACTORS
REACTOR COOLING SYSTEMS
SAFETY INJECTION
THERMAL ANALYSIS
THERMAL CONDUCTIVITY
THERMAL STRESSES
TURBULENT FLOW