CIESC Journal ›› 2022, Vol. 73 ›› Issue (12): 5343-5354.DOI: 10.11949/0438-1157.20221233

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Evolution mechanism of water freezing phase interface in porous media at mesoscale

Wensong WANG1(), Yingying YANG1,2(), Zhoulin CHEN1, Qingyu YANG1, Shuaihua LI1, Weidong WU1   

  1. 1.School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
    2.Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, Shanghai 200093, China
  • Received:2022-09-14 Revised:2022-11-10 Online:2023-01-17 Published:2022-12-05
  • Contact: Yingying YANG

介观尺度下多孔介质内水结冰相界面演化机制研究

王文松1(), 杨英英1,2(), 陈周林1, 杨晴雨1, 李帅华1, 武卫东1   

  1. 1.上海理工大学能源与动力工程学院,上海 200093
    2.上海市动力工程多相流动与传热重点实验室,上海 200093
  • 通讯作者: 杨英英
  • 作者简介:王文松(1998—),男,硕士研究生,wwsusst@163.com
  • 基金资助:
    国家自然科学基金项目(52006146)

Abstract:

Heat and mass transfer problems in the freezing process of water in porous media generally exist in the fields of engineering in cold region, food freezing and preservation, construction, and pavement freeze-thaw damage. In this study, the evolution mechanism of water freezing phase interface in porous media is studied at the mesoscale by experiments and simulations. Firstly, the evolution of phase interface and temperature field during water freezing in microchannels with pore radius of 500 μm was studied by unidirectional freezing experiment. Then, the effects of boundary temperature, pore space and pore structure on the evolution of phase interface and water freezing rate were studied through numerical simulation. The results show that the relative curvature of the phase interface decreases with the decrease of pore radius. In the channel, the relative curvature decreases firstly and then increases, making the phase change from concave to convex. The temperature in the channel decreases quickly and then slowly with time, and the rate is related to the temperature gradient. Supercooling causes the formation of supercooled zone between 0℃ isotherm and phase interface. The smaller the pore space is, the stronger the sudden temperature gradient in the pore channel is, which hinders heat transfer. Among the four pore structures studied in this paper, the circular straight-row has the highest freezing rate.

Key words: mesoscale, porous media, freezing, capillary force, phase interface

摘要:

多孔介质内水冻结过程的传热传质问题普遍存在于寒区工程、食品冷冻保鲜和建筑、路面冻融破坏等领域。本研究在介观尺度下对多孔介质内水结冰相界面的演化机理进行了实验与模拟研究。首先通过单向冻结实验,研究了孔隙半径500 μm微孔道内水冻结过程中相界面及温度场演变规律。然后通过数值模拟,研究了边界温度、孔隙间距、孔隙结构对相界面演变规律和水冻结速率的影响。结果表明,相界面相对曲率随孔隙半径减小而减小,在孔道中,相对曲率先减小后增大,使相界面从凹形向凸形变化。孔道内温度随时间下降先快后慢,其速率与温度梯度有关。过冷引起0℃等温线与相界面之间过冷带的形成。孔隙间距越小,孔道内的温度梯度突跃越剧烈,阻碍传热。在本文研究的四种孔隙结构中,圆形直排冻结速率最大。

关键词: 介观尺度, 多孔介质, 冻结, 毛细力, 相界面

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