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本文用玻璃珠模拟堆积型多孔介质,用Hotdjsk热常数分析仪对不同含湿率下玻璃珠堆积颗粒的导热系数进行测量,并利用CCD结合体式显微镜观察不同含湿率下试样孔隙内的水分形态及颗粒聚集状态,研究分析水分含量、水分形态,颗粒聚集状态对堆积型多孔介质导热系数的影响及机理。实验结果表明;试样的导热系数随含湿率的增大呈非单调递增趋势.不同含湿率下堆积型多孔介质孔隙内水分形态不同,其对颗粒的作用不同,颗粒间出现聚集,从而导致颗粒间距离发生变化,进而表观体积变化。水分含量、水分形态、颗粒间间距的变化均会影响介质的导热系数大小,介质导热系数的变化趋势是由这些影响因素综合决定的。
In this paper, glass beads were used to simulate the porous media, and the thermal conductivity of glass beads with different moisture content was measured by Hotdjsk thermal constant analyzer. The moisture in the pores of samples with different moisture contents was observed by CCD combined microscope Morphology and particle aggregation state, study the influence of moisture content, water morphology, particle aggregation state on the thermal conductivity of the porous media and the mechanism. The experimental results show that the thermal conductivity of the sample increases non-monotonously with the increase of the moisture content.The pore morphology of the porous media with different moisture contents has different morphologies, which have different effects on the particles and accumulate between the particles Resulting in changes in the distance between the particles, and thus the apparent volume change. The changes of moisture content, water morphology and interparticle spacing all affect the thermal conductivity of the medium. The trend of the thermal conductivity of the medium is determined by these factors.