非饱和土壤内部水-气界面特性的微CT分析  

MICRO-CT ANALYSIS OF PORE-SCALE WATER-AIR INTERFACIAL BEHAVIOR IN UNSATURATED SOIL

作　　者：王华军[1] 冯露菲 王雪丽[1] 谢佳音[1] Wang Huajun Feng Lufei Wang Xueli Xie Jiayin(School of Energy and Environment Engineering, Hebei University of Technology, Tianjin 300401, China)

机构地区：[1]河北工业大学能源与环境工程学院,天津300401

出　　处：《太阳能学报》2016年第12期3104-3109,共6页Acta Energiae Solaris Sinica

基　　金：国家自然科学基金(50906020);河北省自然科学基金(E2015202181)

摘　　要：以不同粒径玻璃微珠为对象,通过高分辨率Micro-CT测量获得非饱和土壤内部水-气界面的分布状态特征,并采用欧拉数(Eu)表征土壤内部孔隙的连通特性。结果表明,Eu随饱和度S变化可分为3个阶段,其中当S<25%时,Eu随饱和度线性降低;当25%<S<35%时,Eu随饱和度缓慢降低,直至减小至零;当S>35%时,Eu呈现负值,且变化非常微弱。土壤内部的水-气接触面积随饱和度的增加呈现快速上升而后逐渐下降的整体变化趋势。最后,以热导率为例,量化水-气界面状态变化对不同温度下土壤宏观热物性的影响,并分析土壤内部水-气扩散与流动机制。Aiming at micro glass beads with different diameters, the pore-scale water-air interfacial behavior in unsaturated soil was observed and measured by using a micro-CT scanner with high resolutions, and the Euler number was used to analyze the connectivity of micro pores in soil. The results show that the variations of the Euler number with saturation S can be divided into three major stages： when S〈25%, the Euler number with S decrease linearly; when 25% 〈S〈 35%, the Euler number with S decrease very slowly until zero; when S〉35%, the Euler number is negative and varies very weakly. As the saturation increases, the water-air interfacial area increase quickly and then decrease gradually. Finally, taking thermal conductivity as an example, the effect of the changes of the water-air interfacial status on the macroscopic thermophysical properties of soil under different temperatures is quantitatively analyzed, and water- air diffusion and flow mechanism in soil is revealed.

关 键 词：非饱和土壤 水-气接触面积 CT分析 欧拉数 临界饱和度 

分 类 号：TK124[动力工程及工程热物理—工程热物理]