标题： 反应流中的持续不完全混合 显示英文标题

标题： Persistent incomplete mixing in reactive flows

摘要： 我们提出了一种有效的随机对流-扩散-反应（SADR）模型，该模型解释了在双分子反应传输中通常观察到的不完全混合现象。 与传统的对流-弥散-反应模型不同，SADR模型将机械混合和扩散混合描述为两个独立的过程。 在SADR模型中，机械混合由随机对流速度驱动，其方差由机械弥散系数给出。 扩散混合被建模为菲克扩散，使用有效扩散系数。 我们证明了这两个系数的和等于弥散系数，但只有有效扩散系数对混合控制的反应有贡献，这表明在定义确定性方程和弥散系数的代表性体积尺度上，此类系统不会完全混合。 我们使用Gramling等人的实验结果\cite{Gramling}来表明，在多孔介质中的传输和双分子反应中，SADR模型比传统的弥散模型要准确得多，后者可能高估反应产物的浓度高达60%。 显示英文摘要

摘要： We present an effective stochastic advection-diffusion-reaction (SADR) model that explains incomplete mixing typically observed in transport with bimolecular reactions. Unlike traditional advection-dispersion-reaction models, the SADR model describes mechanical and diffusive mixing as two separate processes. In the SADR model, mechanical mixing is driven by random advective velocity with the variance given by the coefficient of mechanical dispersion. The diffusive mixing is modeled as a Fickian diffusion with the effective diffusion coefficient. We demonstrate that the sum of the two coefficients is equal to the dispersion coefficients, but only the effective diffusion coefficient contributes to the mixing-controlled reactions, indicating that such systems do not get fully mixed at the Representative Elementary Volume scale where the deterministic equations and dispersion coefficient are defined. We use the experimental results of Gramling et al. \cite{Gramling} to show that for transport and bimolecular reactions in porous media, the SADR model is significantly more accurate than the traditional dispersion model, which overestimates the concentration of the reaction product by as much as 60\%.