Analysis of Characteristics of Boiling Heat Transfer over Micro-wire
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摘要: 沸腾换热是一种高效换热方式。基于本课题组搭建的可视化池内沸腾实验台，以直径为0.1，0.2 mm加热丝上的沸腾换热为研究对象，利用高速相机与电子显微镜探究过冷状态下微细加热丝上气泡的状态，分析热流密度和过冷度对加热丝上气泡脱离直径及生长时间的影响。结果表明：在过冷状态下，加热丝上的气泡会出现4种扫荡现象，并且在气泡长大过程中出现射流现象，在热流密度3.35×106 W/m2、主液体温度60℃时，直径为0.2 mm加热丝上气泡的射流现象可持续13 s；在热流密度4.53×106 W/m2、主液体温度为70℃时，直径为0.1 mm加热丝上气泡出现了多射流现象；主液体温度达到70℃时，气泡扫荡现象强烈，气泡的脱离直径与生长时间均显著减小。Abstract: Boiling heat transfer is a highly effective mode of heat transfer. Based on the visually experimental platform for pool boiling designed by research group, taking the boiling heat transfer over micro-wires with the diameters of 0.1, 0.2 mm as objects, the states of bubbles over the micro-wire under sub-cooled condition were studied with a high speed camera and the electronic microscope. The influence of heat flux and sub-cooling degree on the departure diameter and growth time of the bubble over micro-wire were analyzed, respectively. The results show that four kinds of bubbles sweeping movements and jet flow in the growth process can be observed on the heated micro-wire. The bubble jet flow continues for 13 s on the heated wire with the diameter of 0.2 mm, when the heat flux is 3.35×106 W/m2 and mainstream temperature is at 60℃. And the multi jet phenomenon appears over the bubble on the heated wire with diameter of 0.1 mm under the condition of heat flux 4.53×106 W/m2 and mainstream temperature at 70℃. When the temperature of mainstream reaches 70℃, the bubble sweeps strongly on the wire, therefore, the bubble departure diameter and growth time are significantly reduced.
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Keywords:
- boiling heat transfer /
- bubble sweeping /
- bubble jet /
- departure diameter
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[1] 杨世铭,陶文铨. 传热学[M]. 北京:高等教育出版社,2006:315-320. [2] 林瑞泰. 沸腾换热[M]. 北京:科学出版社,1988:11-13. [3] 刘小芳. 射流曝气微细气泡的PIV测量[J].安徽工业大学学报(自然科学版),2012, 29(2):167-170. [4] 戴欣怡,刘亦鹏,包轶颖,等. 低温气液两相流中Taylor气泡的合并[J].过程工程学报,2013, 13(5):776-780. [5] 楚化强,徐靖,顾明言,等. 基于统计窄谱带及关联K模型的气固非灰辐射特性研究[J]. 安徽工业大学学报(自然科学版), 2014, 31(1):1-5. [6] NUKIYAMA S. The maximum and minimum value of heat transmitted from a metal to boiling water under atmosphere pressure[J]. International Journal of Heat and Mass Transfer, 1966, 9(12):1419-1433.
[7] PAUL D D, ABDEL-KHALIK S I. A statistical analysis of saturated nucleate boiling along a heated wire[J]. International Journal of Heat and Mass Transfer, 1983, 26(4):509-519.
[8] PASCUAL C C, JETER S M, ABDEL-KHALIK S I. A statistical analysis of EHD-enhanced nucleate boiling along a heated wire[J]. International Journal of Heat and Mass Transfer, 2001, 44(6):1201-1212.
[9] 王昊. 微细丝上过冷沸腾核化多样性与近壁气泡动力特性[D]. 北京:清华大学,2004:41-115. [10] 王昊,彭晓峰. 加热丝上核态沸腾时气泡间的热相互作用[J]. 航空动力学报,2002, 17(2):241-245. [11] 陆建峰,彭晓峰,丁静. 微细丝上气泡射流间的相互作用特性[J]. 航空动力报,2010, 25(2):264-269. [12] 彭晓峰,陆建峰,丁静. 加热丝上气泡射流的动力学特征[J]. 化工学报,2009, 60(10):2433-2437. [13] ZHOU L, WEI L, LI Y, et al. Bubble circling phenomena in subcooled nucleate pool boiling on microwires[J]. International Journal of Heat and Mass Transfer, 2013, 64:945-951.
[14] 李媛园. 微加热丝表面池核沸腾过程中气泡动态的数值模拟[D]. 北京:华北电力大学,2013:13-41. [15] WANG J, LI F, LI X. Bubble explosion in pool boiling around a heated wire in surfactant solution[J]. International Journal of Heat and Mass Transfer, 2016, 99:569-575.
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