首页> 外文期刊>Journal of Contaminant Hydrology >Multispecies hydrodynamic dispersion under high concentration gradients
【24h】

Multispecies hydrodynamic dispersion under high concentration gradients

机译:高浓度梯度下的多物种水动力分散

获取原文
获取原文并翻译 | 示例
       

摘要

Recent research suggests that when high concentration gradients (HCG) are present, resulting sharp density differences can cause the dispersive flux relationship to deviate from its classical Fickian form. This paper presents stable, upward, miscible displacement experiments conducted in two different types of porous media for a wide range of concentration differences between resident and displacing fluids. The considered groundwater velocities ranged from advection-dominated transport to velocities where the contribution of molecular diffusion is important, with the corresponding Peclet numbers ranging from 0.2 to 320. In addition to single component displacing fluids, mixtures consisting of multiple solutes were considered. The results of this study provide further evidence that classical Fick's law over-estimates the dispersion coefficient under HCG conditions. The decrease in the apparent dispersion coefficient is shown to be a nonlinear function of both concentration difference and groundwater velocity. This observation is attributed to gravitational effects at the sub-continuum scale which are not directly accounted for in classical variable density advection/dispersion models. Mixture experiments showed that the dispersive behaviors of individual components in a groundwater contaminant mixture are coupled.
机译:最近的研究表明,当存在高浓度梯度(HCG)时,由此产生的急剧的密度差异可能会导致色散通量关系偏离其经典的Fickian形式。本文介绍了在两种不同类型的多孔介质中进行的稳定,向上,可混溶的驱替实验,该实验针对的是驻留流体和驱替流体之间的广泛浓度差异。考虑的地下水速度范围从对流为主的运输到分子扩散的贡献很重要的速度,相应的Peclet数在0.2到320之间。除了单组分驱替液外,还考虑了由多种溶质组成的混合物。这项研究的结果提供了进一步的证据,表明经典Fick定律高估了HCG条件下的色散系数。表观弥散系数的减小是浓度差和地下水速度的非线性函数。该观察结果归因于次连续尺度上的重力效应,而经典可变密度对流/弥散模型中并未直接考虑重力效应。混合实验表明,地下水污染物混合物中各个组分的分散行为是相关的。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号