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Flow Reduction in Pore Networks of Packed Silica Nanoparticles: Insights from Mesoscopic Fluid Models
Langmuir ( IF 3.7 ) Pub Date : 2022-06-22 , DOI: 10.1021/acs.langmuir.2c01038
Yidong Xia 1 , Qi Rao 1 , Ahmed Hamed 1 , Joshua Kane 2 , Viktoriya Semeykina 3 , Ilya Zharov 3 , Milind Deo 4 , Zhen Li 5
Affiliation  

A modified many-body dissipative particle dynamics (mDPD) model is rigorously calibrated to achieve realistic fluid–fluid/solid interphase properties and applied for mesoscale flow simulations to elucidate the transport mechanisms of heptane liquid and water, respectively, through pore networks formed by packed silica nanoparticles with a uniform diameter of 30 nm. Two million CPU core hours were used to complete the simulation studies. Results show reduction of permeability by 54–64% in heptane flow and by 88–91% in water flow, respectively, compared to the Kozeny–Carman equation. In these nanopores, a large portion of the fluids are in the near-wall regions and thus not mobile due to the confinement effect, resulting in reduced hydraulic conductivity. Moreover, intense oscillations in the calculated flow velocities also indicate the confinement effect that contests the external driven force to flow. The generic form of Darcy’s law is considered valid for flow through homogeneous nanopore networks, while permeability depends collectively on pore size and surface wettability. This fluid-permeability dependency is unique to flow in nanopores. In addition, potential dependence of permeability on pore connectivity is observed when the porosity remains the same in different core specimens.

中文翻译:

填充二氧化硅纳米粒子孔隙网络中的流量减少:来自介观流体模型的见解

修改后的多体耗散粒子动力学 (mDPD) 模型经过严格校准,以实现真实的流体-流体/固体界面特性,并应用于中尺度流动模拟,以阐明庚烷液体和水分别通过由填充物形成的孔隙网络的传输机制直径为 30 nm 的二氧化硅纳米颗粒。200 万 CPU 内核小时用于完成模拟研究。结果显示,与 Kozeny-Carman 方程相比,庚烷流量和水流量的渗透率分别降低了 54-64% 和 88-91%。在这些纳米孔中,大部分流体位于近壁区域,因此由于限制效应而不能移动,从而导致水力传导率降低。而且,计算出的流速中的强烈振荡也表明限制效应与外部驱动力相抗衡。达西定律的一般形式被认为适用于通过均匀纳米孔网络的流动,而渗透性共同取决于孔径和表面润湿性。这种流体渗透性依赖性对于在纳米孔中流动是独特的。此外,当孔隙度在不同岩心样品中保持相同时,观察到渗透率对孔隙连通性的潜在依赖性。
更新日期:2022-06-22
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