Air-Water Tests on Counter-current Flow Limitation at Lower End of Vertical Pipes Simulating Lower Part of Steam Generator U-tube

Abstract

*+ $ù RST%&26 \b *+ 7Ö î ×H288 789 7Ö î *+ 9:7 8C& ,;<=>2 8 9 a c? 0*+ 9:78C& @642789 7Ö09 \ 78 ABó x789 CD} ÞE5FGH/Na93ab a`p¡' "$1 9789ìí7/CD0EÞ*0N`9 78C& 9ab 0`3 I02J S¤0c f 134K0Ra93789L ¹# ì aeMN O;P5±b 8 8 9 a cd 5 H bS¤0QRóô078\bp¡¬ ae1W b010Sb Abstract Air-water tests on counter-current flow limitation (CCFL) were carried out using vertical pipes with the diameter of D=20 mm and a sharp lower edge which simulated the lower part of U-tubes in a steam generator. Flow patterns were observed to identify the location of CCFL occurrence, and effects of the pipe length L and the water level in the upper tank h on CCFL were measured under the conditions of L=100-700 mm and h=100-600 mm. As a result, CCFL appeared at the upper end under the conditions of L/D=5 and h/D=5, but at the lower end for L/D≧15 and h/D=5～30. In the case of the CCFL occurrence at the lower end, L and h did not affect CCFL characteristics. Using the Wallis parameters, J G

Effects of Fluid Properties on Countercurrent Flow Limitation in Vertical Pipes

“…シャープエッジ下端での CCFL(CCFL-L)を対象 として空気・水実験を行い、Wallis 相関式におい て代表長さ w として直径 D を用いると CCFL 特 性をよく整理できることを明らかにした [3]。 また、 蒸気・水実験 [4]と凝縮実験 [5]を行い、CCFL-L の 相関式を導出した [5]。シャープエッジ上端での CCFL(CCFL-U)については、空気・水実験を行 い w としてラプラス長さ L を用いるべきである ことを明らかにし [6]、従来データ [7]を含めて CCFL-U の相関式を導出した [8]。また、前報 [9] では、上端・下端ともラウンドエッジでの従来デ ータを用いて管内での CCFL(CCFL-P)について 検討し、w ≈ D 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E-03…”

Interfacial Friction Factor for Counter-Current Gas-Liquid Flows in Vertical Pipes

“…や直径 30 mm での Zapke and Krӧger [8] [9]. Kusunoki [18], U-tube Kusunoki [10], SW Kusunoki [9], AW Bharathan [7] Zapke [8] Kusunoki [10] …”