三面加热窄矩形通道内单汽泡生长过程可视化研究
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摘要
本文以去离子水为工质,对三面加热窄矩形通道内单汽泡生长过程进行实验研究,利用可视化手段拍摄三面加热窄矩形通道内汽泡生长状态图像。通过汽泡周期曲线与图像进行对照,分析汽泡生长的物理过程及产生机理。实验过程中发现4种汽泡行为:窄矩形通道内窄边处汽泡分为浮升、聚合、连续性生长三大类,中间加热面仅观测到一类单汽泡快速生长。与传统单面加热面相比,窄边处的汽泡脱离直径更大,汽泡发生的变形更明显。本文重点分析了不同过冷度下汽泡的生长机理、影响因素、直径变化规律、以及汽泡脱离点。实验研究发现,在高过冷度下汽泡底部最先开始发生变形,在中过冷度下汽泡的底部和顶部都发生不同程度的变形,而在低过冷度下汽泡的生长形态保持一致。
In this paper, the grow process of single bubble in a narrow rectangular channel heated on three sides is experimentally investigated. Deionized water is used as working medium and the image of bubble growth state in the narrow rectangular channel heated on three sides is photographed by visualization method. By comparing the cycle curve of bubble with the image, the physical process and mechanism of the bubble growth are analyzed. Four kinds of bubble behaviors are found in the experiment: The bubbles at the narrow edge of the narrow rectangular channel can be divided into three states: buoyancy lift, coalescence and continuous growth. Single bubble is observed on the middle heating surface. Comparing with the bubbles on the traditional single-side heating surface, the departure diameter of bubble on the middle heating surface at the narrow edge is larger and the deformation of the bubble is more pronounced. In this paper, the growth mechanism, influencing factors, diameter variation law, and bubble detachment point of the bubbles under different supercooling are analyzed. The experimental results show that the deformation first begins at the bottom of bubbles under high subcooling, and the bottom and top of the bubbles are deformed to varying degrees under moderate undercooling but the growth pattern of bubbles remains the same under low undercooling.
In this paper, the grow process of single bubble in a narrow rectangular channel heated on three sides is experimentally investigated. Deionized water is used as working medium and the image of bubble growth state in the narrow rectangular channel heated on three sides is photographed by visualization method. By comparing the cycle curve of bubble with the image, the physical process and mechanism of the bubble growth are analyzed. Four kinds of bubble behaviors are found in the experiment: The bubbles at the narrow edge of the narrow rectangular channel can be divided into three states: buoyancy lift, coalescence and continuous growth. Single bubble is observed on the middle heating surface. Comparing with the bubbles on the traditional single-side heating surface, the departure diameter of bubble on the middle heating surface at the narrow edge is larger and the deformation of the bubble is more pronounced. In this paper, the growth mechanism, influencing factors, diameter variation law, and bubble detachment point of the bubbles under different supercooling are analyzed. The experimental results show that the deformation first begins at the bottom of bubbles under high subcooling, and the bottom and top of the bubbles are deformed to varying degrees under moderate undercooling but the growth pattern of bubbles remains the same under low undercooling.
引文
[1]于志家,孙成新,赵宗昌,等.竖直矩形通道内液体流动沸腾气泡动力学研究[J].工程热物理学报,2001,22(3):354-358YU Zhijia, SUN Chengxin, ZHAO Zongchang, et al. Studies on of Bubble Growth on Vertical Heating Wall for Liquid Flow Boiling in a Rectangular Conduit[J]. Journal of Engineering Thermophysics, 2001, 22(3):354-358
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[8] Zeitoun O, Shoukri M. Bubble Behavior and Mean Diameter in Subcooled Flow Boiling[J]. Journal of Heat Transfer, 1996, 118(1):110-116
[9]徐建军,陈炳德,王小军.竖直矩形窄缝通道滑移汽泡聚合作用可视化实验研究[J].原子能科学技术,2011, 45(5):548-553XU Jianjun, CHEN Bingde, WANG Xiaojun. Experimental Visualization Coalesced Interaction of Sliding Bubble Near Wall in Vertical Narrow Rectangular Channel[J].Atomic Energy Science and Technology, 2011, 45(5):548-553
[10] Prodanovic V, Fraser D, Salcudean M. Bubble Behavior in Subcooled Flow Boiling of Water at Low Pressures and Low Flow Rates[J]. International Journal of MultiphaseFlow, 2002, 28(1):1-19
[11] Yang C, Kawara Z, Yokomine T, et al. Visualization Study on Bubble Dynamical Behavior in Subcooled Flow Boiling under Various Subcooling Degree and Flowrates[J]. International Journal of Heat&Mass Transfer, 2016,93:839-852
[12]唐继国,阎昌琪,孙立成,等.气泡微细化沸腾过程中气泡冷凝破裂现象[J].化工学报,2014,65(8):2902-2907TANG Jiguo, YAN Changqi, SUN Licheng, et al. Condensation and Collapse of Bubbles in Region of Microbubble Emission Boiling[J]. Journal of Chemical Industry and Engineering, 2014, 65(8):2902-2907
[13]毕景良,李雪芳,柯道友,等.液体过冷度对沸腾换热中汽泡合并及传热的影响[J].工程热物理学报,2015,36(8):1737-1741BI Jingliang, LI Xuefang, Christopher D M, et al. Subcooling Effect on Coalesence and Heat Transfer in Pool Boiling[J]. Journal of Engineering Thermophysics, 2015,36(8):1737-1741
[14] Kalman H, Mori Y H. Experimental Analysis of a Single Vapor Bubble Condensing in Subcooled Liquid[J]. Chemical Engineering Journal, 2002, 85(2/3):197-206
[15]陈德奇.窄流道内汽泡生长和脱离特性及汽泡行为对压降的影响[D].重庆:重庆大学,2010CHEN Deqi. The Character of Bubble Growth and Bubble Detachment and the Effect of Bubble Behavior on Pressure Drop in Narrow Channel[D]. Chongqing:Chongqing University, 2010
[2] Han J L, Sang Y L. Heat Transfer Correlation for Boiling Flows in Small Rectangular Horizontal Channels with Low Aspect Ratios[J]. International Journal of Multiphase Flow, 2001, 27(12):2043-2062
[3] Fujita Y, Ohta H, Uchida S, et al. Nucleate Boiling Heat Transfer and Critical Heat Flux in Narrow Space Between Rectangular Surfaces[J]. International Journal of Heat&Mass Transfer, 1988, 31(2):229-239
[4] Aoki S, Inoue A, Aritomi M, et al. Experimental Study on the Boiling Phenomena within a Narrow Gap[J]. International Journal of Heat and Mass Transfer, 1982, 25(7):985-990
[5]袁德文,潘良明,陈德奇,等.窄流道内压力对汽泡动力学特性的影响[J].工程热物理学报,2009, 30(4):605-607YUAN Dewen,PAN Liangming,CHEN Deqi,et al.Pres-sure Effects of Narrow Channel on the Characteristics of Bubble Dynamics[J]. Journal of Engineering Thermophysics, 2009, 30(4):605-607
[6]胡健,高璞珍,许超,等.窄矩形通道内过冷流动沸腾汽泡生长模型研究[J].原子能科学技术,2014, 48(12):2213-2218HU Jian, GAO Puzhen, XU Cao, et al. Experimental Study on Bubble Growth Model of Subcooled Flow Boiling in Narrow Rectangular Channel[J]. Atomic Energy Science and Technology, 2014, 48(12):2213-2218
[7]郭昂,杨立新.竖直矩形窄缝通道过冷流动沸腾的实验研究[J].工程热物理学报,2014, 35(9):1836-1839GUO Ang, YANG Lixin. Experimental Investigation of Subcooled Flow Boiling in Vertical Rectangular Narrow Channel[J]. Journal of Engineering Thermophysics, 2014,35(9):1836-1839
[8] Zeitoun O, Shoukri M. Bubble Behavior and Mean Diameter in Subcooled Flow Boiling[J]. Journal of Heat Transfer, 1996, 118(1):110-116
[9]徐建军,陈炳德,王小军.竖直矩形窄缝通道滑移汽泡聚合作用可视化实验研究[J].原子能科学技术,2011, 45(5):548-553XU Jianjun, CHEN Bingde, WANG Xiaojun. Experimental Visualization Coalesced Interaction of Sliding Bubble Near Wall in Vertical Narrow Rectangular Channel[J].Atomic Energy Science and Technology, 2011, 45(5):548-553
[10] Prodanovic V, Fraser D, Salcudean M. Bubble Behavior in Subcooled Flow Boiling of Water at Low Pressures and Low Flow Rates[J]. International Journal of MultiphaseFlow, 2002, 28(1):1-19
[11] Yang C, Kawara Z, Yokomine T, et al. Visualization Study on Bubble Dynamical Behavior in Subcooled Flow Boiling under Various Subcooling Degree and Flowrates[J]. International Journal of Heat&Mass Transfer, 2016,93:839-852
[12]唐继国,阎昌琪,孙立成,等.气泡微细化沸腾过程中气泡冷凝破裂现象[J].化工学报,2014,65(8):2902-2907TANG Jiguo, YAN Changqi, SUN Licheng, et al. Condensation and Collapse of Bubbles in Region of Microbubble Emission Boiling[J]. Journal of Chemical Industry and Engineering, 2014, 65(8):2902-2907
[13]毕景良,李雪芳,柯道友,等.液体过冷度对沸腾换热中汽泡合并及传热的影响[J].工程热物理学报,2015,36(8):1737-1741BI Jingliang, LI Xuefang, Christopher D M, et al. Subcooling Effect on Coalesence and Heat Transfer in Pool Boiling[J]. Journal of Engineering Thermophysics, 2015,36(8):1737-1741
[14] Kalman H, Mori Y H. Experimental Analysis of a Single Vapor Bubble Condensing in Subcooled Liquid[J]. Chemical Engineering Journal, 2002, 85(2/3):197-206
[15]陈德奇.窄流道内汽泡生长和脱离特性及汽泡行为对压降的影响[D].重庆:重庆大学,2010CHEN Deqi. The Character of Bubble Growth and Bubble Detachment and the Effect of Bubble Behavior on Pressure Drop in Narrow Channel[D]. Chongqing:Chongqing University, 2010