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不同材料和球径的多孔球层内水的过冷度分析
引用本文:章学来,刘田田,赵群志,梁笑阳,徐蔚雯.不同材料和球径的多孔球层内水的过冷度分析[J].化工学报,2015,66(6):2011-2016.
作者姓名:章学来  刘田田  赵群志  梁笑阳  徐蔚雯
作者单位:上海海事大学蓄冷技术研究所, 上海 201306
基金项目:国家自然科学基金项目(50976064,51376115)。@@@@supported by the National Natural Science Foundation of China
摘    要:为研究多孔球层的存在对水过冷的影响, 采用不同材料(铝、不锈钢、玻璃)和不同球径(5、8、11 mm)的多孔球层固体基底进行了实验研究。由于水的过冷度并非一定值, 因此进行多次实验并采用统计方法进行分析。实验结果表明:多孔球层内蒸馏水的过冷度分布比纯蒸馏水分布更集中, 且过冷度值比纯蒸馏水小;同材质不同球径多孔球层内水的平均过冷度整体上随着球径减小而减小;固体基底的热导率越大, 多孔球层内水的过冷度分布越集中且平均过冷度也越小;固体基底的热导率较小时, 易壁面成核, 沿壁面由外向内缓慢结晶, 相变时间明显多于均匀成核, 而均匀成核一旦形成晶核, 晶核就会瞬间长大, 形成的冰疏松, 因此工程应用中应尽量避免壁面成核。

关 键 词:过冷度  多孔介质  统计方法  热导率  
收稿时间:2014-10-29
修稿时间:2015-03-04

Analysis of supercooling degree of water in ball-packed porous structure of different materials and diameters
ZHANG Xuelai,LIU Tiantian,ZHAO Qunzhi,LIANG Xiaoyang,XU Weiwen.Analysis of supercooling degree of water in ball-packed porous structure of different materials and diameters[J].Journal of Chemical Industry and Engineering(China),2015,66(6):2011-2016.
Authors:ZHANG Xuelai  LIU Tiantian  ZHAO Qunzhi  LIANG Xiaoyang  XU Weiwen
Affiliation:Institute of Cool Thermal Storage Technology, Shanghai Maritime University, Shanghai 201306, China
Abstract:In order to study the effects of bead-packed porous structure, balls of different materials such as aluminum, stainless steel and glass with different diameters of 5, 8 and 11 mm are added into distilled water forming porous media. Since the supercooling degree of water is not a certain value, the experiments are repeated many times at the same cooling condition and analyzed with statistical methods. The results show that the distribution of the supercooling degree of distilled water in porous media is more concentrated than that of pure distilled water and the supercooling degree of water in porous media is smaller. The average supercooling degree of distilled water decreases with decreasing diameter of the same material balls on the whole. The larger the thermal conductivity of solid substrate is, the more concentrated the distribution of supercooling degree of distilled water in porous media and the smaller the average supercooling degree. In addition, the heterogeneous nucleation is more likely to occur when the thermal conductivity of the solid substrate is small. An annulus solid ice begins to grow slowly from the inside wall to the center region and the phase change time is longer than homogeneous nucleation. Once the crystal nucleus is formed, it will grow up instantly, forming the loose ice of homogeneous nucleation. Therefore, the heterogeneous nucleation should be avoided in engineering application.
Keywords:supercooling degree  porous media  statistical methods  thermal conductivity
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