| 过冷池沸腾中气泡聚并对壁面换热影响的实验研究 |
AbdoulayeCoulibaly,林曦鹏,毕景良,柯道友( ) |
| Effect of bubble coalescence on the wall heat transfer during subcooled pool boiling |
| Coulibaly Abdoulaye,Xipeng LIN,Jingliang BI,M. Christopher David() |
| Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China |
摘要:
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| 文章导读 | |||
| 摘要该文实验研究了气泡聚并对核态池沸腾换热的影响。在恒壁温的边界条件下,利用微加热器阵列加热液态FC-72产生气泡,同时利用高速数据采集系统测量特定区域的热流密度。由于气泡之间液体层的蒸发和气泡聚并后产生的振荡,沸腾过程中发生气泡聚并时热流密度的波动远强于加热表面仅有单气泡生成时的情形。与单气泡成核相比,气泡聚并所产生的振荡提高了加热表面的再润湿频率,从而显著增加了平均传热。观测还表明,由于气泡之间的液体层被仍处于惯性生长阶段的气泡推离,气泡聚并速度非常快时并不会伴随热流量的增加。实验结果表明: 当无量纲的聚并数Ncoal>0.2时,气泡聚并能够增强换热; 反之,当Ncoal<0.2时,气泡聚并则会减弱换热。 | |||
| 关键词 ：微加热器阵列,气泡动力学,气泡聚并,热传递,池沸腾 | |||
| Abstract：This study experimentally investigated the effects of bubble coalescence on nucleate pool boiling. A micro heater array was used to generate vapor bubbles in FC-72 liquid with constant surface temperature boundary conditions while the heat flux at selected locations was measured using a high speed data acquisition system. The heat flux for boiling with coalescence was found to fluctuate much more than when only a single bubble formed on the surface due to the vaporization of the liquid layer trapped between the bubbles and oscillation of the bubbles after coalescence. These oscillations significantly increased the average heat transfer by increasing the frequency of rewetting of the heated surfaces compared to single bubble nucleation. The observations also showed that very fast coalescence events were not accompanied by an increase in the heat transfer rate as the liquid layer between the bubbles was physically pushed away by the rapid bubble growth during the inertial bubble growth stage instead of evaporating. The results show that the heat transfer increases for the dimensionless coalescence number, Ncoal, more than 0.2 but decreases for Ncoal less than 0.2. | |||
| Key words：micro heater arraybubble dynamicsbubble coalescenceheat transferpool boiling | |||
| 收稿日期: 2013-01-04 出版日期: 2015-04-16 | |||
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| 基金资助:国家“九七三”重点基础研究项目(2011CB706904) | |||
| 引用本文: |
| AbdoulayeCoulibaly, 林曦鹏, 毕景良, 柯道友. 过冷池沸腾中气泡聚并对壁面换热影响的实验研究[J]. 清华大学学报（自然科学版）, 2014, 54(2): 240-246. Coulibaly Abdoulaye, Xipeng LIN, Jingliang BI, M. Christopher David. Effect of bubble coalescence on the wall heat transfer during subcooled pool boiling. Journal of Tsinghua University(Science and Technology), 2014, 54(2): 240-246. |
| 链接本文: |
| http://jst.tsinghuajournals.com/CN/或 http://jst.tsinghuajournals.com/CN/Y2014/V54/I2/240 |
图表:
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| 加热器阵列上23个微加热器的分布 |
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| 微加热器阵列中央4个加热器的布线 |
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| 电子反馈控制回路 |
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| 沸腾装置原理图 |
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| 气泡聚并及新气泡的形成和聚并(所有加热器温度为45 ℃) |
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| 加热器4的热流密度变化曲线(横轴所示时间与 |
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| 合并过程中液体排出时加热器7的热流密度变化曲线 |
参考文献:
| [1] | Hsu S T, Schmidt F W. Measured variations in local surface temperatures in pool boiling of water[J]. Journal of Heat Transfer (US) , 1961, 83(3): 254-260. |
| [2] | Rogers T F, Mesler R B. An experimental study of surface cooling by bubbles during nucleate boiling of water[J]. AIChE Journal, 1964, 10(5): 656-660. |
| [3] | Cooper M G, Lloyd A J P. The microlayer in nucleate pool boiling[J]. International Journal of Heat and Mass Transfer, 1969, 12(8): 895-913. |
| [4] | Watwe A A, Hollingsworth D K. Liquid crystal images of surface temperature during incipient pool boiling[J]. Experimental Thermal and Fluid Science, 1994, 9(1): 22-33. |
| [5] | Kim J, Bae S W, Whitten M W, et al. Boiling heat transfer measurements on highly conductive surfaces using microscale heater and temperature arrays [C]// Proc of the 4th Microgravity Fluid Physics and Transport Phenomena Conference. Cleveland, OH, USA, 1998. |
| [6] | Demiray F, Kim J. Microscale heat transfer measurements during pool boiling of FC-72: Effect of subcooling[J]. International Journal of Heat and Mass Transfer, 2004, 47(14): 3257-3268. |
| [7] | Chen T, Chung J N. Heat-transfer effects of coalescence of bubbles from various site distributions[J]. Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 2003, 459(2038): 2497-2527. |
| [8] | Bonjour J, Clausse M, Lallemand M. Experimental study of the coalescence phenomenon during nucleate pool boiling[J].Experimental Thermal and Fluid Science, 2000, 20(3): 180-187. |
| [9] | Qiu D, Son G, Dhir V K, et al.Dynamics of single and multiple bubbles and associated heat transfer in nucleate boiling under low gravity conditions[J].Annals of the New York Academy of Sciences, 2002, 974(1): 378-397. |
| [10] | Golobic I, Petkovsek J, Kenning D. Bubble growth and horizontal coalescence in saturated pool boiling on a titanium foil, investigated by high-speed IR thermography[J]. International Journal of Heat and Mass Transfer, 2012, 55(4): 1385-1402. |
| [11] | Coulibaly A, Lin X, Bi J, et al.Bubble coalescence at constant wall temperatures during subcooled nucleate pool boiling[J]. Experimental Thermal and Fluid Science, 2013, 44: 209-218. |
| [12] | Rayleigh L VIII. On the pressure developed in a liquid during the collapse of a spherical cavity[J]. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, 1917, 34(200): 94-98. |
| [13] | Mikic B B, Rohsenow W M. Bubble growth rates in non-uniform temperature field[J]. Progress in Heat and Mass Transfer, 1969, 2: 283-292. |
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