| 砂?重晶石粉填料导热性能与传热机制研究 |
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| 引用本文： | 贾海梁,朱子贤,周阳,孙强.砂?重晶石粉填料导热性能与传热机制研究[J].煤田地质与勘探,2022,50(11):162-173. |
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| 作者姓名： | 贾海梁 朱子贤 周阳 孙强 |
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| 作者单位： | 1.西安科技大学 建筑与土木工程学院，陕西 西安 710054 |
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| 基金项目： | 陕西省地质勘查基金项目(61202110382) |
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| 摘 要： | 地埋管地源热泵是浅层地热能利用的一种主要形式，回填材料的热物性尤其导热系数是影响热泵系统换热效率的关键。以砂和重晶石粉作为研究对象，探究不同重晶石粉掺比(体积分数)以及不同饱和度样品导热系数的变化规律；并基于体视镜、核磁共振分析等宏细观实验，揭示重晶石粉对回填材料导热系数提高的机制；最后，通过数值模拟手段研究该回填材料导热性能对换热效率的影响。研究表明:重晶石粉对回填材料导热系数的影响显著，掺比20%重晶石粉对回填材料导热系数提高的效果最好，最高可使导热系数提高52.09%；水的含量对导热系数影响也很显著，样品饱水后导热系数明显增加，相比干燥样品提高了4~5倍；重晶石粉对回填材料导热系数的提高主要由包裹效应和填隙效应引起，包裹效应为重晶石粉将砂颗粒表面包裹，而填隙效应则是重晶石粉将砂颗粒之间的孔隙填充；数值模拟结果证明重晶石粉提高回填材料导热系数进而提高地源热泵换热效率的可行性。研究成果为地源热泵回填材料的选择提供了参考。
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| 关 键 词： | 导热性能 换热效率 回填材料 重晶石粉 地源热泵 宏细观实验 数值模拟 |
| 收稿时间： | 2022-03-28 |
Heat conduction performance and transfer mechanism of sand-barite powder backfill materials |
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| Institution: | 1.College of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an 710054, China2.Shaanxi Institute of Geological Survey, Xi’an 710054, China3.College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, China |
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| Abstract: | The ground source heat pump of buried pipeline is a major form of shallow thermal energy utilization, and the thermophysical properties of backfill materials, especially the thermal conductivity, are the key factors affecting the heat transfer efficiency of the heat pump system. In this paper, the variation law of thermal conductivity of the sand-barite powder samples at different barite powder mixing ratio (volume fraction) and saturation was studied. The mechanism of improving the thermal conductivity of backfill materials with barite powder was revealed based on the macroscopic and microscopic experiments such as stereoscope and nuclear magnetic resonance analysis. In addition, the influence of the heat conduction performance of this backfill materials on heat transfer efficiency was studied by numerical simulation. The study shows that barite powder has a significant effect on the thermal conductivity of backfill materials, and the barite powder at the mixing ratio of 20% has best effect on improving the thermal conductivity of backfill materials, which could improve the thermal conductivity by 52.09% at maximum. Water content also has a significant effect on the thermal conductivity, and the thermal conductivity of the saturated sample is significantly increased, which is 4?5 times higher than that of dry sample. The improvement of the thermal conductivity of backfill materials by barite powder is mainly caused by the package and filling effect. Specifically, the package effect is to wrap the sand particles with barite powder, while the filling effect is to fill the pores between sand particles with barite powder. The numerical simulation results prove that it is feasible to improve the heat transfer efficiency of ground source heat pump by enhancing the thermal conductivity of backfill materials with barite powder. Generally, the research results provide reference for the selection of backfill materials of ground source heat pump. |
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