Prediction of vortex penetration depth at thermal stratification by cavity flow in a branch pipe with closed end (effect of heat radiation condition on temperature fluctuations) |
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| Authors: | Kouji Shiina Tsutomu Kawamura Masaya Ohtsuka Tadashi Mizuno Masakazu Hisatsune Kenji Ogura Kouichi Tanimoto Toshihiko Fukuda Yasuhiko Minami Shoichi Moriya Haruki Madarame |
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| Affiliation: | 1. Industrial Systems R&D Laboratory, Hitachi, Ltd., Japan;2. Hitachi Works, Hitachi, Ltd., Japan;3. Power Systems & Service Company, Toshiba Corp., Japan;4. Takasago R&D Center, Mitsubishi Heavy Industries, Ltd., Japan;5. Nuclear Power Engineering Department, Tokyo Electric Power Company, Japan;6. Nuclear Power Division, Kansai Electric Power Co., Inc., Japan;7. Abiko Research Laboratory, Central Research Institute of Electric Power Industry, Japan;8. Department of Engineering Physics and Mechanics, The University of Tokyo, Japan |
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| Abstract: | In a branch pipe with one closed end, the cavity flow penetrates into the branch pipe from the main loop and a thermal boundary layer occurs because the cavity flow is a hot fluid, but heat removal causes a colder fluid in the branch pipe. This thermal stratification may affect the structural integrity. Therefore, a pipe design standard to suppress thermal fatigue should be established. The pipe design standard consists of the maximum penetration depth Lsv and the minimum penetration depth Lsh. In order to establish an evaluation method for Lsh, a visualization test and a temperature fluctuation test were carried out. A theoretical formula for thermal stratification was introduced from the heat balance model. Then the model was used to obtain an empirical equation from the map of fluid temperature fluctuation. This method can predict the vortex penetration depth by cavity flow in horizontal branch pipes. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 36(1):38–55, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20135 |
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| Keywords: | thermal stress thermal fatigue thermal satisfaction heat radiation temperature fluctuation vortex penetration cavity flow branch pipe |
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