A lattice Boltzmann investigation of steady-state fluid distribution, capillary pressure and relative permeability of a porous medium: Effects of fluid and geometrical properties
A lattice Boltzmann investigation of steady-state fluid distribution, capillary pressure and relative permeability of a porous medium: Effects of fluid and geometrical properties
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DOI：
10.1016/j.advwatres.2018.04.009
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发表时间：
2018-06-01
影响因子：
4.7
通讯作者：
Li, Ling
中科院分区：
文献类型：
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作者：
Li, Zi;Galindo-Torres, Sergio;Li, Ling
采用基于二维多孔介质的Shan-Chen多组分格子Boltzmann模型（SCMC-LBM），对毛细力主导下的同时稳态两相流进行了数值模拟。我们专注于分析流体分布（即，WP流体-固体、NP流体-固体和流体-流体界面面积）以及受流体和几何性质影响的毛细管压力对饱和度曲线（即，润湿性、粘合强度、孔径分布和比表面积）。并通过视有效渗透率和启动压力梯度探讨了这些性质对相对渗透率-饱和度关系的影响。SCMC-LBM模拟表明，由于粘性流固相互作用，在固体表面形成了一层薄的WP流体膜，导致WP流体离散分布，降低了WP流体的流动性。此外，粘合剂的相互作用提供了另一个来源的毛细管压力，除了毛细管力，然而，这并不影响流动性的NP流体。在非均质多孔介质中，大的粘附强度和细的孔隙可以增强膜流体效应。在稳态入渗过程中，不仅NP流体受到毛细阻力，WP流体也受到毛细阻力。降低非均质多孔介质的润湿性、增大平均孔隙半径和改善流体连通性可以减轻毛管压力效应。基于SCMC-LBM的研究，阐明了膜流体和毛细管压力在两相流系统中的作用。研究结果对改进基于力平衡的稳态入渗宏观渗流方程具有重要意义。
Simulations of simultaneous steady-state two-phase flow in the capillary force-dominated regime were conducted using the state-of-the-art Shan-Chen multi-component lattice Boltzmann model (SCMC-LBM) based on two-dimensional porous media. We focused on analyzing the fluid distribution (i.e., WP fluid-solid, NP fluid-solid and fluid-fluid interfacial areas) as well as the capillary pressure versus saturation curve which was affected by fluid and geometrical properties (i.e., wettability, adhesive strength, pore size distribution and specific surface area). How these properties influenced the relative permeability versus saturation relation through apparent effective permeability and threshold pressure gradient was also explored. The SCMC-LBM simulations showed that, a thin WP fluid film formed around the solid surface due to the adhesive fluid-solid interaction, resulting in discrete WP fluid distributions and reduction of the WP fluid mobility. Also, the adhesive interaction provided another source of capillary pressure in addition to capillary force, which, however, did not affect the mobility of the NP fluid. The film fluid effect could be enhanced by large adhesive strength and fine pores in heterogeneous porous media. In the steady-state infiltration, not only the NP fluid but also the WP fluid were subjected to the capillary resistance. The capillary pressure effect could be alleviated by decreased wettability, large average pore radius and improved fluid connectivity in heterogeneous porous media. The present work based on the SCMC-LBM investigations elucidated the role of film fluid as well as capillary pressure in the two-phase flow system. The findings have implications for ways to improve the macroscopic flow equation based on balance of force for the steady-state infiltration.