Bulletin of the American Physical Society
72nd Annual Meeting of the APS Division of Fluid Dynamics
Volume 64, Number 13
Saturday–Tuesday, November 23–26, 2019; Seattle, Washington
Session Q38: Porous Media Flow General III |
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Chair: Pejman Sanaei, NYIT Room: 620 |
Tuesday, November 26, 2019 7:45AM - 7:58AM |
Q38.00001: Effects of particles diffusion and membrane pore elasticity on membrane filtration performance Pejman Sanaei, Shi Yue Liu, Zhengyi Chen Membrane filters fouling, which is an inevitable consequence of particle removal from the feed solution, is sensitive to the flow rate and the internal morphology and structure of membrane. In a very slow filtration process or during the late stage of filtration, when the flow is naturally very slow and P'eclet number is small, particle diffusion is essential and can not be neglected. Beside this, real membranes have complex geometry, and consist of a series of bifurcating elastic pores, which decrease in size as the membrane is traversed. In this talk, we introduce two first-principle models considering asymptotic analysis based on the membrane pores aspect ratio and a distinguished limit of the particle P'eclet number. We consider the effects of diffusion for a single membrane pore as well as elasticity in a membrane with branching structure on filtration performance. In the first model, pressure driven flow is considered through the pore and advection-diffusion equation for the particle concentration is coupled with novel fouling models. Furthermore, in the second model, we investigate the membrane pores evolution under two different forcing mechanisms (constant pressure and flux) and describe how the membrane internal morphology changes due to its fouling and elasticity. [Preview Abstract] |
(Author Not Attending)
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Q38.00002: Simulations of small particle deposition on a membrane filter pore using the immersed boundary method Scott Weady, Pejman Sanaei Membrane filters have widespread use in the medical, biotech and food science industries, among many others, and their design relies on modeling the flow and fouling mechanisms relevant to each specific application. In this talk, we describe immersed boundary method simulations of the fouling of a membrane filter pore by small particle deposition. The distribution of particles evolves according to an advection-diffusion equation driven by Stokes flow which is coupled to an adsorbtion model. We consider pressure driven flow through a rigid pore as well as constant flux through an elastic pore, and compare our results with those of several asymptotic models based on the order of the P\'eclet number and the pore aspect ratio. [Preview Abstract] |
Tuesday, November 26, 2019 8:11AM - 8:24AM |
Q38.00003: Asymmetric Two-phase Flows Resistance in Homogeneous and Heterogeneous Anisotropic Porous Microstructure Dario Maggiolo, Federico Toschi, Francesco Picano, Srdjan Sasic, Henrik Strom Two-phase flows in porous media exhibit anomalous behaviours at low capillary numbers due to the complex mechanism of interaction between flow spatial configuration and topology of the microstructure. In this study, we investigate the asymmetrical nature of the two-phase flow resistance induced by the anisotropic features of the porous microstructure. We perform pore-scale direct numerical simulations of two-phase flows in porous media composed of solid particles with different shapes and orientations, using the Lattice-Boltzmann method. The results indicate that the infiltration of a fluid into a single pore is regulated by the topological traits of the pore, including its anisotropy. These traits determine a geometrical characteristic length of the pore $\ell_p$ quantifying the flow resistance, which is directional-dependent: if the capillary length $\ell_\gamma=\gamma/p_c$ (i.e. the ratio between surface tension and capillary pressure) falls below the characteristic pore length $\ell_\gamma<\ell_p$, pore infiltration occurs, otherwise the fluid remains trapped. We extend the analysis to heterogeneous anisotropic microstructure in order to investigate the effect of the spatial configuration of the pores on the global flow resistance. [Preview Abstract] |
Tuesday, November 26, 2019 8:24AM - 8:37AM |
Q38.00004: Hydrodynamic driven dissolution in porous media with fluid-filled cavities Mojdeh Rasoulzadeh, Wyatt Kuehster Hydrodynamics is a key player in defining the dissolution rate and dissolution hotspots in porous media with complex pore structure including embedded cavities. Cavities rearrange the pressure and flow field locally and affect the dissolution. On the cavity boundary, the fluid velocity maintains the concentration gradient and provides a fresh source of the solvent that facilitates dissolution. Given the characteristics of cavity and the porous zone, vorticities may form, and the cavity may partially or fully participate in the overall flow. In order to predict the dissolution hotspots properly, it is crucial to define the flow field accurately. We use the analytical models of flow in a porous medium including a random distribution of fluid-filled cavities. Darcy's law is coupled to the Stokes flow for spheroidal shaped cavities. On the cavity boundary, a no-jump condition on normal velocities, jump on pressures, and the generalized Beavers-Joseph-Saffman condition on tangential velocities is applied. A sequential non-iterative approach is applied to handle the coupling between hydrodynamics and dissolution. Transport of solute provides the concentration of solute at every grid point then the dissolved minerals is updated by PHREEQC. Dissolution hotspots are detected. [Preview Abstract] |
Tuesday, November 26, 2019 8:37AM - 8:50AM |
Q38.00005: Viscous Transport in Eroding Porous Media Shang-Huan Chiu, Bryan Quaife, Nicholas Moore Erosion is a fluid-mechanical process that is present in many geological phenomena such as groundwater flow. We present a boundary integral equation formulation to simulate two-dimensional erosion in porous media. One numerical challenge is accurately resolving the interactions between nearly touching eroding bodies at low porosity. We present a Barycentric quadrature method to resolve these interactions and compare it with the standard trapezoid rule. We compute the velocity, vorticity, and tracer trajectories in the geometries that include dense packings of 20, 50, and 100 eroding bodies. Like in our previous work~[1], we observe quick expending channels between close bodies, flat faces developing along the regions of near contact, and bodies eventually vanishing. Finally, having computed tracer trajectories, we characterize the transport inside of eroding geometries by computing and analyzing the tortuosity and anomalous diffusion rates. ${}^1$B. D. Quaife {\it et al.}, J. Comput. Phys. {\bf 375}, 1 (2018). [Preview Abstract] |
Tuesday, November 26, 2019 8:50AM - 9:03AM |
Q38.00006: ABSTRACT WITHDRAWN |
Tuesday, November 26, 2019 9:03AM - 9:16AM |
Q38.00007: Experimental study of permeability of oriented fiber arrays. Qianhong Wu, Zenghao Zhu In this paper, a systematic study is performed to examine the permeability of a highly organized, oriented porous layer. Despite of extensive theoretical studies for the Darcy permeability of dilute or concentrated, oriented fiber array when the flow is either perpendicular or parallel to the fiber axis, there is a lack of research for the porosity between 0.3 and 0.8. Furthermore, no experimentally validated solutions have been reported to estimate the permeability of oriented fiber arrays where the angle between the fiber axis and the flow direction is in the range of 0 degree to 90 degree. We present in this paper an experimental study to examine the Darcy permeability of 3-D printed fiber arrays with different orientations. New correlations have been obtained when the porosity of the fiber array is in the range of 0.3 and 0.8. Furthermore, we have proved that, it is appropriate to use a linear combination method, based on the permeabilities of the fiber array at two distinct orientations, to predict the permeability of the fiber array at other orientations. The study presented herein has important applications in both biological systems and industrial applications, e.g. soft porous lubrication. [Preview Abstract] |
Tuesday, November 26, 2019 9:16AM - 9:29AM |
Q38.00008: Dewatering saturated, networked suspensions with a screw press Tom Eaves, Daniel Paterson, Duncan Hewitt, Neil Balmforth, Mark Martinez A model is presented for the dewatering of a saturated two-phase porous medium in a screw press. The model accounts for the detailed two-phase rheological behaviour of the pressed material and splits the press into two zones, an initial well-mixed constant-pressure region followed by an axial transport region in which the total pressure steadily increases. In this latter region, a slowly-varying helical coordinate transformation reduces the dynamics to an annular bi-axial compression of the two-phase porous medium. Unlike previous modeling, the transition point between the two zones is determined self consistently, rather than set a priori, and the pressure along the length of the press is deduced from the rheology of the two-phase flow rather than averaging the two-phase dynamics over a cross-section of the press. The model is compared to experimental observations of the dewatering of a paper-making fibre suspension and of a clay slurry, and is shown to reproduce operational data. [Preview Abstract] |
Tuesday, November 26, 2019 9:29AM - 9:42AM |
Q38.00009: Rayleigh-Taylor mixing in a porous medium Guido Boffetta, Matteo Borgnino, Stefano Musacchio Rayleigh-Taylor mixing in a porous medium is studied by high-resolution direct numerical simulations of the Darcy-Boussinesq equations in both two and three dimensions. The width of the mixing layer is found to grow linearly in the limit of small diffusivity, in agreement with the dimensional expectation. A different growth rate is observed in two and three dimensions. The characteristic transverse scale, a measure of the typical plume size, grows slower following a diffusive law: as a consequence plumes became more elongated during the time evolution. The evolution of the density flux, quantified by the Nusselt number, is studied as a function of the Darcy-Rayleigh number. [Preview Abstract] |
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