Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Experimental and Analytical Investigation on Thermal Stratification under Natural Circulation Cooling

Get access (open in a dialog) DOI: 10.1615/IHTC15.ncv.008506
pages 5265-5287

Abstrakt

In relation to severe accident management of pressurized water reactor (PWR) under station blackout (SBO) condition, experimental and analytical investigation was carried out on heat transfer and fluid flow in natural circulation cooling. Time variation of temperature distributions in vessel and piping was measured under various water temperature and vessel geometries, heat exchange rate, and heating and cooling conditions. Time variation of flow rate of water is measured by electromagnetic flow meter. Temperature at each point of the vessel decreased very gradually when cooling started. When the interface of thermal stratification passed the point, the temperature of water rapidly decreased. Temperature in upper part of the vessel is kept high when other part is cooled by natural circulation cooling. Velocity of interface of thermal stratification is dependent on flow rate of natural circulation. Flow rate of natural circulation is dependent on water temperature, heat exchange rate. Simulation of natural circulation cooling was carried out using CFD Code ANSYS FLUENT Ver.14.0 and agreed with experimental data. Some methods of mixing of thermal stratification were proposed. Experiments of additional heating or bubble injection were carried out and mixing of thermal stratification is confirmed.