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ISSN 0254-0096 CN 11-2082/K

太阳能学报 ›› 2022, Vol. 43 ›› Issue (5): 1-9.DOI: 10.19912/j.0254-0096.tynxb.2020-0932

• •    下一篇

砂土导热特性及表观热导率预测关联式模型

褚召祥, 王义江2, 赵光思2, 董凯军1, 孙钦1, 王泽桂2   

  1. 1.广东省新能源和可再生能源研究开发与应用重点实验室,广州 510640;
    2.深部岩土力学与地下工程国家重点实验室,徐州 221116;
    3.中国矿业大学电气与动力工程学院,徐州 221116
  • 收稿日期:2020-09-07 出版日期:2022-05-28 发布日期:2022-11-28
  • 通讯作者: 褚召祥(1987—),男,博士(后)、助理研究员,主要从事岩土多孔介质传热传质方面的研究。chulongxiang@cumt.edu.cn
  • 基金资助:
    国家自然科学基金(42107156; 41672343; 51978653); 广东省新能源和可再生能源研究开发与应用重点实验室开放基金(E039kf0501)

HEAT CONDUCTION CHARACTERISTICS OF SANDS AND APPARENT THERMAL CONDUCTIVITY PREDICTIVE CORRELATION MODEL

Chu Zhaoxiang, Wang Yijiang2, Zhao Guangsi2, Dong Kaijun1, Sun Qin1, Wang Zegui2   

  1. 1. Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China;
    2. State Key Laboratory for Geo-Mechanics and Deep Underground Engineering, Xuzhou 221116, China;
    3. School of Electrical and Power Engineering, China University of Mining and Technology, Xuzhou 221116, China
  • Received:2020-09-07 Online:2022-05-28 Published:2022-11-28

摘要: 以细观尺度假设条件下砂土多孔/颗粒介质周期性单元结构为几何模型,采用COMSOL Multiphysics软件开展针对不同孔隙率和饱和度、不同边界条件下,固-液-气三相砂土稳态热传导过程有限元数值实验。研究结果表明,砂土热导率随孔隙率的增加而降低,随饱和度的增加而增加,变化速率均逐渐减小;相同孔隙率和饱和度工况下方形单元结构采用恒壁温+绝热+第3类边界条件的组合方式时,热导率反向计算结果最优;基于数值实验结果建立的砂土热导率与孔隙率、饱和度之间的指数、幂律函数关系式计算获得的热导率在低、高饱和度区与实验回归模型预测结果吻合度较高;与理论和试验研究相比,数值模拟/实验可以有效表征孔隙/颗粒尺度砂土导热特性,进而以土壤物理参数为基础建立具有较高精度的砂土表观热导率预测关联式模型。

关键词: 浅层地热能, 砂土, 多孔介质, 孔隙率, 饱和度, 热导率, 数值模拟

Abstract: The steady state heat conduction processes of multi-phase (solid-liquid-gas) and porous/granular sandy soil were simulated via finite element method (COMSOL Multiphysics) in a periodic unit cell under ideal assumptions, based on which the heat conduction characteristics and change laws of its effective thermal conductivity (ETC) were obtained. The results indicate that the ETC of the unit cell decreases with the porosity while increases with the saturation, and the decrease and increase tendencies, however, slow down gradually, showing good agreements with existing theoretical and experimental studies. The adversely calculated ETC using the simulated results under the combination of boundary conditions of constant wall temperature + adiabatic boundary + the third Robin boundary condition has the best performance. Based on the numerical experiment results, the established exponent/power-law function between the ETC of sand and porosity, saturation provides higher coincidence degree with experimental regression model in low and high saturation region. Compared with theoretical and experimental research, the numerical simulation/experiment can effectively capture the microscopic heat conduction characteristics of sands and establish the ETC predictive correlation model using basic soil physical parameters with acceptable accuracy.

Key words: shallow geothermal energy, sand, porous media, porosity, saturation, thermal conductivity, numerical simulation

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