Diffusion in pore networks: Effective medium theory and smooth field approximation
Diffusion in pore networks: Effective medium theory and smooth field approximation
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孔隙网络中的扩散：有效介质理论和光滑场近似
DOI：
10.1002/aic.690331011
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发表时间：
1987
期刊：
影响因子：
3.7
通讯作者：
S. V. Sotirchos
中科院分区：
文献类型：
--
作者：
V. Burganos;S. V. Sotirchos
考虑了一类多孔网络中的扩散问题，给出了一个估计扩散系数的方法。有效介质理论用于获得网络的有效电导，然后用于从第一物理原理开始并利用均匀电导的孔隙网络满足平滑场近似的观察来确定有效扩散率。与那些从大网络的传输方程的精确解得到的估计的颗粒内扩散系数的比较，揭示了高精度和可靠性的方法。一些孔隙网络的结果表明，光滑场假设不应被任意采用，因为它总是预测更高的有效扩散系数比确切的，在某些情况下超过一个数量级。
The problem of diffusion in pore networks of a certain class is considered, and a procedure for estimating diffusivities is formulated. The effective-medium theory is used to obtain an effective conductance for the network, which is then used to determine the effective diffusivity starting from first physical principles and utilizing the observation that a network of pores of uniform conductance satisfies the smooth field approximation. Comparison of the estimated intraparticle diffusivities with those obtained from the exact solution of the transport equation for large networks reveals high accuracy and reliability of the method. Results for a number of pore networks show that the smooth field assumption should not be employed arbitrarily since it always predicts higher effective diffusion coefficients than the exact ones, by more than one order of magnitude in some cases.