We investigate the impact of pore‐scale heterogeneity on reactive mixing using experimental data from inert fluid‐fluid displacement in a quasi 2‐D porous medium. We interpret the invading and defending fluids as the conservative components A+C and B+C of the instantaneous irreversible bimolecular chemical reaction A+B→C and determine the reaction product C. We find strong growth of the reaction rate at short and intermediate times due to deformation of the mixing interface and heterogeneity‐induced increase of the mixing area. This behavior is captured by a dispersive lamella approach that quantifies the mixing dynamics at the interface in terms of temporally evolving effective dispersion coefficients. The latter capture the dominant controls on the evolution of the mixing interface, namely, advective heterogeneity and transverse mixing. Reactive transport formulations based on constant hydrodynamic dispersion coefficients are not able to describe the observed behavior due to the lack of complete mixing on the support scale, which is required for these approaches to hold. These results shed some new light on the origins of heterogeneity‐induced mixing and reaction dynamics in porous media and their systematic upscaling.

中文翻译：

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从实验保守传输数据评估和预测孔隙尺度反应混合

我们使用准二维多孔介质中惰性流体-流体驱替的实验数据，研究了孔尺度异质性对反应混合的影响。我们将入侵和防御流体解释为瞬时不可逆双分子化学反应A + B → C的保守成分A + C和B + C，并确定反应产物C。由于混合界面的变形和异质性导致的混合面积的增加，我们发现反应速率在短时间内和中间时间都有强劲的增长。这种行为通过色散薄片方法来捕获，该方法根据时间上演变的有效色散系数来量化界面处的混合动力学。后者捕获了混合界面演化的主要控制因素，即对流异质性和横向混合。基于恒定的水动力分散系数的反应性运输配方无法描述所观察到的行为，原因是缺乏在支撑规模上的完全混合，而这些都是保持这些方法所必需的。