Assessment and Prediction of Pore‐Scale Reactive Mixing From Experimental Conservative Transport Data
Assessment and Prediction of Pore‐Scale Reactive Mixing From Experimental Conservative Transport Data
复制标题
根据实验保守传输数据评估和预测孔隙尺度反应混合
作者：
Lazaro J. Perez;J. Hidalgo;Alexandre Puyguiraud;J. Jiménez‐Martínez;M. Dentz
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隙尺度非均匀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的保守组分A+C和B+C，并确定了反应产物C。我们发现，由于混合界面的变形和非均匀性引起的混合面积的增加，反应速率在短时间和中间时间内强劲增长。这种行为被捕获的色散层的方法，量化的混合动力学在界面上的时间演变的有效色散系数。后者捕获的混合界面的演变，即平流不均匀性和横向混合的主导控制。基于恒定流体动力学弥散系数的反应性输运公式不能描述所观察到的行为，这是由于缺乏支持尺度上的完全混合，这是这些方法所需的。这些结果为多孔介质中非均匀性诱导的混合和反应动力学及其系统放大的起源提供了一些新的线索。
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.