Abstract
Saturated boiling of two-phase natural circulation has been experimentally investigated based on a natural circulation device with narrow rectangular channels. When heating power reaches a certain range, it is possible to observe the phenomenon of saturated boiling and flow pattern transition in the system. The results show the heat transfer coefficient of saturated boiling decreases with the increasing of pressure, heating power and size of narrow rectangle channels. The buoyancy force causing mixed convection decreases the heat transfer coefficient. Finally, a dimensionless number is introduced, which reflects length to width ratio of rectangular narrow section and Rayleigh number, in order to revise the presented correlation. All errors fall within the range of ±15%.
Kurzfassung
Gesättigtes Sieden des Zweiphasen-Naturumlaufs wurde auf der Basis einer Naturumlaufvorrichtung mit schmalen rechteckigen Kanälen experimentell untersucht. Bei entsprechender Wärmeleistung lässt sich in dem System das Phänomen des gesättigten Siedens und des Übergangs von Strömungsverhältnissen beobachten. Die Ergebnisse zeigen, dass der Wärmeübergangskoeffizient des gesättigten Siedens mit steigendem Druck, Wärmeleistung und Größe der schmalen rechteckigen Kanäle sinkt. Die Auftriebskraft, die gemischte Konvektion erzeugt, verringert den Wärmeübergangskoeffizient. Eine dimensionslose Zahl, die das Länge-zu-Weite Verhältnis der rechteckigen schmalen Abschnitte und die Rayleigh-Zahl wiedergibt, wird eingeführt, um die dargelegte Korrelation wiederzugeben. Alle Fehler liegen in einem Bereich von ±15%.
References
1 TongMingwei, ShiChengming, XinMingdao: Heat transfer enhancement in a two phase closed thermosyphon [J]. Journal of Engineering Thermophysics5 (1984) 58–60Search in Google Scholar
2 Ishibashi, Nishikawak: Saturated boiling heat transfer in narrow spaces [J]. International Journal of Heat and Mass Transfer12 (1969) 863–86610.1016/0017-9310(69)90153-7Search in Google Scholar
3 ShenXiuzhong, MiyazakiKeiji, XuJijun: A study on the flow boiling heat transfer characteristics in norrow inside heating annuli [J]. Chinese Journal of Nuclear Science and Engineering21 (2001) 244–251Search in Google Scholar
4 ShenXiuzhong, LiuYang, ZhangQinshun: Flow boiling heat transfer correlation for narrow channel [J]. Nuclear Power Engineering23 (2002) 80–83Search in Google Scholar
5 PanLiangming, XinMingdao, HeChuan, et al.: Subcooled boiling heat transfer in the vertical narrow rectangular channel [J]. Journal of Engineering Thermophysics23 (2002) 215–217Search in Google Scholar
6 LiuTiancai, JinHuajin, YuanLuzheng: Flow blockage accident analysis for China advanced research reactor [J]. Nuclear Power Engineering27 (2006) 32–35Search in Google Scholar
7 ChenChong, GaoPuzhen, WangChang: Experimental research of flow boiling heat transfer characteristics in narrow channel [J]. Atomic Energy Science and Technology48 (2014) 435–440Search in Google Scholar
8 HuangLihao, TaoLeren, RuiShengjun, et al.: Experimental study of the boiling heat exchange characteristics of a flow in a vertical rectangular narrow channel [J]. Journal of engineering for thermal energy and power1 (2013) 53–56Search in Google Scholar
9 Jiang, S. Y.; Yao, M. S. et al.: Experimental simulation study on start-up of the 5 MW nuclear heating reactor [J]. Nuclear Engineering and Design158 (1995) 111–12310.1016/0029-5493(95)01020-ISearch in Google Scholar
10 ZhouTao: Passive concept and technology [M]. Tsinghua University Press, 2016Search in Google Scholar
11 Yao, S. C.; Chang, Y.: Pool boiling heat transfer in a confined space [J]. International Journal of Heat & Mass Transfer26 (1983) 841–84810.1016/S0017-9310(83)80108-2Search in Google Scholar
12 Motlagh, S. Y.; Soltanipour, H.: Natural convection of Al2O3-water nanofluid in an inclined cavity using Buongiorno's two-phase model [J]. International Journal of Thermal Sciences111 (2017) 310–32010.1016/j.ijthermalsci.2016.08.022Search in Google Scholar
13 Zhang, L.; Hua, M.; Zhang, X. et al.: Visualized investigation of gas–liquid stratified flow boiling of water in a natural circulation thermosyphon loop with horizontal arranged evaporator [J]. International Journal of Heat & Mass Transfer102 (2016) 980–99010.1016/j.ijheatmasstransfer.2016.06.089Search in Google Scholar
14 ShengCheng: Research on developing mechanisms in narrow rectangular channel under natural circulation flow condition [D]. North China Electric Power University, 2013Search in Google Scholar
15 YuKaiqiu, SunLicheng, YanChangqi: Applicability of “Chen” type methods for predicting boiling heat transfer in mini-channels [J]. Nuclear Power Engineering31 (2010) 24–28Search in Google Scholar
16 Sun, L.; Mishima, K.: An evaluation of prediction methods for saturated flow boiling heat transfer in mini-channels [J]. International Journal of Heat & Mass Transfer52 (2009) 5323–532910.1016/j.ijheatmasstransfer.2009.06.041Search in Google Scholar
17 YangShiming, TaoWenquan: Heat transfer [M]. Higher Education Press, 2006Search in Google Scholar
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