Multispecies Reactive Transport in a Microporous Rock: Impact of Flow Heterogeneity and Reversibility of Reaction
Multispecies Reactive Transport in a Microporous Rock: Impact of Flow Heterogeneity and Reversibility of Reaction
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微孔岩石中的多物质反应输运：流动非均质性和反应可逆性的影响
DOI：
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发表时间：
2020
影响因子：
5.4
通讯作者：
B. Bijeljic
中科院分区：
文献类型：
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作者：
T. D. S. Oliveira;M. Blunt;B. Bijeljic
我们研究孔隙空间非均质性对多孔介质中混合和反应的影响。我们模拟了在三维微孔固结岩石中平行注入不同 pH 值的两股反应物，其孔隙空间通过微分显微 CT 成像解析。作为非均质介质的示例，我们考虑从波特兰碳酸盐样品获得的孔隙结构。我们使用直接数值模拟来研究流动异质性的耦合影响，其特征是速度的广泛分布和化学可逆性对多物种反应的影响。流场是从 Darcy-Brinkman 方程中找到的，而平流扩散方程描述了传输，它与通用的多物种地球化学求解器耦合用于均相反应；忽略沉淀和溶解。我们观察到浓度以及形成和消耗速率的空间分布高度不均匀。对于平流主导的传输，非均质流场导致早期大孔中的显着横向混合，随后由大孔和微孔区域之间的扩散驱动的较慢的混合。形成和消耗的有效速率取决于物种，并且大孔隙度和微孔隙度不同：虽然一些物种在充分混合的区域达到渐近速率，但其他物种由于不完全混合仍然表现出短暂的非单调行为。我们的发现对于理解时间和空间依赖性反应速率行为具有重要意义：需要考虑孔隙空间异质性和可逆反应的耦合影响，作为描述多物种反应传输的关键决定因素。
We study the impact of pore space heterogeneity on mixing and reaction in porous media. We simulate the parallel injection of two streams of reactants at different pH in a three‐dimensional microporous consolidated rock whose pore space was resolved by differential micro‐CT imaging. As an exemplar of a heterogeneous medium, we consider the pore structure obtained from a Portland carbonate sample. We use direct numerical simulation to study the coupled impact of flow heterogeneity, characterized by a wide distribution of velocities and chemical reversibility on multispecies reaction. The flow field is found from the Darcy‐Brinkman equation while the advection‐diffusion equation describes transport, which is coupled to a general multispecies geochemical solver for homogeneous reactions; precipitation, and dissolution are ignored. We observe a highly nonuniform spatial distribution of concentration and rates of formation and consumption. For advection‐dominated transport, the heterogeneous flow field leads to significant transverse mixing in macropores at early times, followed by a slower mixing driven by diffusion between macropore and micropore regions. The effective rates of formation and consumption are species‐dependent and distinct in macroporosity and microporosity: while some species reach an asymptotic rate in well‐mixed regions, others still show a transient nonmonotonic behavior as a consequence of incomplete mixing. Our findings have important implications for the understanding of time‐ and space‐dependent reaction rate behavior: the coupled impact of pore space heterogeneity and reversible reactions need to be taken into account as key determinants to describe multispecies reactive transport.
DOI：
10.1073/pnas.1221373110
发表时间：
2013-03-05
影响因子：
11.1
作者：
Berg, Steffen;Ott, Holger;Stampanoni, Marco
通讯作者：
Stampanoni, Marco
影响因子：
2.6
作者：
Timothy Scheibe;E. M. Murphy;Xingyuan Chen;A. Rice;K. Carroll;B. Palmer;A. Tartakovsky;I. Battiato;B. Wood
通讯作者：
Timothy Scheibe;E. M. Murphy;Xingyuan Chen;A. Rice;K. Carroll;B. Palmer;A. Tartakovsky;I. Battiato;B. Wood
影响因子：
4.7
作者：
Lin, Qingyang;Al-Khulaifi, Yousef;Bijeljic, Branko
通讯作者：
Bijeljic, Branko