Direct numerical simulation of pore-scale flow in a bead pack: Comparison with magnetic resonance imaging observations
Direct numerical simulation of pore-scale flow in a bead pack: Comparison with magnetic resonance imaging observations
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DOI：
10.1016/j.advwatres.2013.01.009
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发表时间：
2013-04
影响因子：
4.7
通讯作者：
Xiaofan Yang;Timothy Scheibe;M. Richmond;W. Perkins;S. J. Vogt;S. Codd;J. Seymour;Matthew I. McKinley
中科院分区：
文献类型：
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作者：
Xiaofan Yang;Timothy Scheibe;M. Richmond;W. Perkins;S. J. Vogt;S. Codd;J. Seymour;Matthew I. McKinley
当前研究的一个重要主体旨在开发用于多孔介质中流动和输运的数值模拟的方法，其明确地解决复杂的孔隙和固体几何形状，并且利用这样的模型来研究基本孔隙尺度过程与更大（即，达西）鳞片。已经开发了许多不同的孔隙尺度模拟的数值方法，并且已经针对简化的几何形状进行了广泛的测试和验证。然而，验证复杂的，三维（3D）的孔隙几何形状，代表天然多孔介质的流体速度的孔隙尺度模拟是具有挑战性的，由于我们有限的能力，以测量在这样的系统中的孔隙尺度的速度。磁共振成像（MRI）的最新进展不仅提供了测量孔隙几何形状的机会，而且还提供了在3D和高空间分辨率的稳态流动条件下的局部流体速度。在本文中，我们提出了一个三维速度场测量亚孔隙分辨率（几十微米）超过厘米级的三维域使用MRI方法。我们利用测得的孔隙几何形状进行三维模拟的Navier-Stokes流在同一域使用直接数值模拟技术。我们提出了一个比较的数值模拟结果与实测速度场。结果表明，数值结果匹配所观察到的速度模式以及整体除了方差和小的系统缩放，这可以归因于已知的实验不确定性的MRI测量。这里提出的比较提供了强有力的孔隙尺度模拟方法的验证和新的见解，在MRI测量孔隙尺度速度的不确定性的解释。这项研究也提供了一个潜在的基准，为未来比较其他孔隙尺度模拟方法。© 2012 Elsevier Science。All rights reserved.
A significant body of current research is aimed at developing methods for numerical simulation of flow and transport in porous media that explicitly resolve complex pore and solid geometries, and at utilizing such models to study the relationships between fundamental pore-scale processes and macroscopic manifestations at larger (i.e., Darcy) scales. A number of different numerical methods for pore-scale simulation have been developed, and have been extensively tested and validated for simplified geometries. However, validation of pore-scale simulations of fluid velocity for complex, three-dimensional (3D) pore geometries that are representative of natural porous media is challenging due to our limited ability to measure pore-scale velocity in such systems. Recent advances in magnetic resonance imaging (MRI) offer the opportunity to measure not only the pore geometry, but also local fluid velocities under steady-state flow conditions in 3D and with high spatial resolution. In this paper, we present a 3D velocity field measured at sub-pore resolution (tens of micrometers) over a centimeter-scale 3D domain using MRI methods. We have utilized the measured pore geometry to perform 3D simulations of Navier–Stokes flow over the same domain using direct numerical simulation techniques. We present a comparison of the numerical simulation results with the measured velocity field. It is shown that the numerical results match the observed velocity patterns well overall except for a variance and small systematic scaling which can be attributed to the known experimental uncertainty in the MRI measurements. The comparisons presented here provide strong validation of the pore-scale simulation methods and new insights for interpretation of uncertainty in MRI measurements of pore-scale velocity. This study also provides a potential benchmark for future comparison of other pore-scale simulation methods. © 2012 Elsevier Science. All rights reserved.