A mobile-mobile transport model for simulating reactive transport in connected heterogeneous fields

Chunhui Lu, Zhiyuan Wang, Yue Zhao, Saubhagya Singh Rathore, Jinge Huo, Yuening Tang, Ming Liu, Rulan Gong, Olaf A. Cirpka, Jian Luo

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Mobile-immobile transport models can be effective in reproducing heavily tailed breakthrough curves of concentration. However, such models may not adequately describe transport along multiple flow paths with intermediate velocity contrasts in connected fields. We propose using the mobile-mobile model for simulating subsurface flow and associated mixing-controlled reactive transport in connected fields. This model includes two local concentrations, one in the fast- and the other in the slow-flow domain, which predict both the concentration mean and variance. The normalized total concentration variance within the flux is found to be a non-monotonic function of the discharge ratio with a maximum concentration variance at intermediate values of the discharge ratio. We test the mobile-mobile model for mixing-controlled reactive transport with an instantaneous, irreversible bimolecular reaction in structured and connected random heterogeneous domains, and compare the performance of the mobile-mobile to the mobile-immobile model. The results indicate that the mobile-mobile model generally predicts the concentration breakthrough curves (BTCs) of the reactive compound better. Particularly, for cases of an elliptical inclusion with intermediate hydraulic-conductivity contrasts, where the travel-time distribution shows bimodal behavior, the prediction of both the BTCs and maximum product concentration is significantly improved. Our results exemplify that the conceptual model of two mobile domains with diffusive mass transfer in between is in general good for predicting mixing-controlled reactive transport, and particularly so in cases where the transfer in the low-conductivity zones is by slow advection rather than diffusion.

Original languageEnglish
Pages (from-to)97-108
Number of pages12
JournalJournal of Hydrology
Volume560
DOIs
StatePublished - May 2018
Externally publishedYes

Funding

The authors thank the constructive comments from three anonymous reviewers. C. Lu would acknowledge financial support of the National Natural Science Foundation of China ( 51679067 ) and the 111 project ( B17015 ). Z. Wang would acknowledge financial support of the National Key Research Project ( 2017YFC0404501 ), the National Natural Science Foundation of China ( 51609144 ) and the Natural Science Foundation of Jiangsu Province ( BK20160143 ). Other financial support includes the National Natural Science Foundation of China ( 51628902 ).

Keywords

  • Mixing
  • Mobile-immobile
  • Mobile-mobile
  • Reactive transport

Fingerprint

Dive into the research topics of 'A mobile-mobile transport model for simulating reactive transport in connected heterogeneous fields'. Together they form a unique fingerprint.

Cite this