A Model for Multiphase and Multicomponent Flow in Porous Media, Built on the Diffuse-Interface Assumption
A Model for Multiphase and Multicomponent Flow in Porous Media, Built on the Diffuse-Interface Assumption
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基于扩散界面假设的多孔介质中多相和多组分流模型
DOI：
10.1007/s11242-009-9405-2
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发表时间：
2010
影响因子：
2.7
通讯作者：
P. Papatzacos
中科院分区：
文献类型：
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作者：
P. Papatzacos
本文提出了一种非化学组分混合物在多孔介质中流动的新理论。在所考虑的例子中，这些成分是碳氢化合物和水。该模型假定孔隙度恒定且均匀，介质的润湿性质近乎中性。流动方程是从孔水平上的平衡方程(质量、动量和能量)出发，在大量的孔上进行平均，使用扩散界面假设，然后用不可逆热力学的方法，从而获得作为组分密度的函数的集体对流速度和组分扩散速度等。当引入均匀温度的简化时，流动方程是Cahn-Hilliard类型(增加了一个考虑引力的项)，其中热力学函数是混合物单位体积的亥姆霍兹自由能。没有相对渗透率。此外，从不需要闪光计算的意义上讲，这组方程是完整的，相分离是计算的一部分。所考虑的数值例子是：(I)引力场中的相分离和(Ii)初态完全分离的锥形。
This article presents a new theory for flow in porous media of a mixture of nonreacting chemical components. In the examples considered, these components are hydrocarbons and water. The model presented assumes that porosity is constant and uniform, and that the wetting properties of the medium are nearly neutral. The flow equations are obtained by starting with the balance equations (mass, momentum, and energy) at pore level, and averaging them over a large number of pores, using the diffuse interface assumption then the methods of irreversible thermodynamics, thus obtaining, among other things, the collective convective velocity and the component-wise diffusive velocities as functions of the component densities. When the simplification of uniform temperature is introduced, the flow equations are of the Cahn–Hilliard type (with an extra term accounting for gravitation) where the thermodynamic function is the Helmholtz free energy per unit volume of the mixture. There are no relative permeabilities. Also, the set of equations is complete in the sense that no flash calculations are necessary, phase segregation being part of the calculation. The numerical examples considered are: (i) phase segregation in a gravitational field and (ii) coning where the initial state is fully segregated.