| 4种NAPLs污染物在二维砂箱中的指进锋面形态特征研究 |
| 摘要点击 2566 全文点击 1677 投稿时间：2012-09-09 修订日期：2012-11-07 |
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| 中文关键词 多孔介质 非水相液体 指进 迁移规律 图像分析 |
| 英文关键词 porous media NAPLs fingering migration image analysis |
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| 中文摘要 |
| 为明确介质和流体性质等因素对非水相液体(NAPLs)在多孔介质中入渗迁移的影响,利用数码图像分析技术对甲苯、柴油、1,2-二氯乙烷和四氯乙烯这4种NAPLs在4种不同粒径多孔介质中的非饱和入渗特性进行了实验研究. 结果表明,数码图像分析技术能够动态、全过程记录NAPLs的迁移锋面; NAPLs在驱替气体过程中会出现指进形式的不稳定流; 指进生长过程中出现分叉、合并和屏蔽等现象; NAPLs的迁移特性受介质性质和流体特性的共同影响,入渗过程中垂向上的迁移速率和污染面积增长率与介质粒径大小呈正相关,与流体密度呈正相关(甲苯除外),入渗过程中形成的指进与介质和流体本身性质也密切相关. 相同时间内,DNAPL相较于LNAPL入渗的距离更深,造成的污染面积更大,其环境风险明显大于LNAPL. |
| 英文摘要 |
| The infiltration characteristics of toluene, diesel, 1,2-dichloroethane and tetrachlorethylene were studied in four different unsaturated porous media to determine the impact of the properties of media and fluids on the infiltration aided by digital image analysis technique. The results indicated that the whole process of NAPLs migration can be recorded dynamically using the digital image analysis technique. The unstable flow "fingering" occurred in the process of infiltration. Fingering mechanisms such as splitting, coalescing, and shielding were observed in the process of fingering. Front morphology of the infiltration was influenced by the properties of porous media and fluids. The vertical migration rates and the growth rates of area development were positively correlated to the size of medium particle and the density of the NAPLs (except for toluene) in the process of infiltrating. The number of fingers and the wavelength of fingering were also closely correlated with the properties of media and fluid. DNAPLs infiltrated faster compared with LNAPLs, which resulted in larger pollution area within the same infiltration time. It can be concluded that the environmental risk of DNAPLs is significantly greater than the LNAPLs. |
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