题目：Characterizing air-water interfacial areas in variably saturated sandy porous media
报告人：  彭胜  副教授
北京师范大学环境学院
时间：11月20日（周四）下午2:30-3:30
地点：方正大厦301会议室

报告内容摘要：
The air-water interface has received increased attention in recent years due to its critical role in many mass and energy transfer processes in variably porous media. It is recognized to play significant role in controlling transport and fate of volatile organic contaminants, pathogens, and colloids, and influencing multi-phase flow. Characterization of air-water interfacial areas is important for better understanding of these processes.
The magnitude of air-water interfacial areas is expected to be dependent on water content, water configuration, porous media properties (e.g., soil texture, grain size distribution, microscopic surface heterogeneity), and bulk density. In this study, gas-phase partitioning tracer tests were used for the measurement of air-water interfacial areas for a series of sandy porous media with different grain size distributions and textures at different water contents. Experiment results showed that the magnitudes of the air-water interfacial areas approached that of the normalized surface areas at very low water content. The change of air-water interfacial areas with changing water saturation was greater for poor-sorted media than for well-sorted media. An empirical equation was developed to describe the observed relationship between air-water interfacial area and water saturation. The coefficients of the equation were found to correlate to the porous medium uniformity coefficient.
Another method, aqueous-phase partitioning tracer method was also applied to one of the media in measuring air-water interfacial areas. Tests were conducted for different water saturations under both wetting-phase drainage and imbibition conditions. Aqueous-phase tracer tests showed consistent measurement with gas-phase tracer tests, while each of them has different suitable measurement ranges.

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