The Complexity of Porous Media Flow Characterized in a Microfluidic Model Based on Confocal Laser Scanning Microscopy an
- PDF / 2,312,071 Bytes
- 25 Pages / 439.37 x 666.142 pts Page_size
- 104 Downloads / 143 Views
The Complexity of Porous Media Flow Characterized in a Microfluidic Model Based on Confocal Laser Scanning Microscopy and Micro‑PIV D. A. M. de Winter1 · K. Weishaupt2 · S. Scheller3 · S. Frey3 · A. Raoof1 · S. M. Hassanizadeh1,2 · R. Helmig2 Received: 31 July 2020 / Accepted: 16 November 2020 © The Author(s) 2020
Abstract In this study, the complexity of a steady-state flow through porous media is revealed using confocal laser scanning microscopy (CLSM). Micro-particle image velocimetry (microPIV) is applied to construct movies of colloidal particles. The calculated velocity vector fields from images are further utilized to obtain laminar flow streamlines. Fluid flow through a single straight channel is used to confirm that quantitative CLSM measurements can be conducted. Next, the coupling between the flow in a channel and the movement within an intersecting dead-end region is studied. Quantitative CLSM measurements confirm the numerically determined coupling parameter from earlier work of the authors. The fluid flow complexity is demonstrated using a porous medium consisting of a regular grid of pores in contact with a flowing fluid channel. The porous media structure was further used as the simulation domain for numerical modeling. Both the simulation, based on solving Stokes equations, and the experimental data show presence of non-trivial streamline trajectories across the pore structures. In view of the results, we argue that the hydrodynamic mixing is a combination of non-trivial streamline routing and Brownian motion by pore-scale diffusion. The results provide insight into challenges in upscaling hydrodynamic dispersion from pore scale to representative elementary volume (REV) scale. Furthermore, the successful quantitative validation of CLSM-based data from a microfluidic model fed by an electrical syringe pump provided a valuable benchmark for qualitative validation of computer simulation results.
* D. A. M. de Winter [email protected] 1
Environmental Hydrogeology, Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
2
Department of Hydromechanics and Modelling of Hydrosystems, University of Stuttgart, Stuttgart, Germany
3
Visualization Research Center, University of Stuttgart, Stuttgart, Germany
13
Vol.:(0123456789)
D. A. M. de Winter et al.
Graphic Abstract
Keywords Confocal laser scanning microscope · Micro-PIV · Porosity · Microfluidic model · Hydrodynamic dispersion · Streamlines
1 Introduction Fluid flow through porous media is a multi-scale process that brings together fundamental laws of physics at the molecular level and empirical relations at macro scale level. We study an intermediate length scale (micrometer–millimeter) to explore difficulties associated with upscaling solute transport, i.e., hydrodynamic dispersion and mixing (Lowe and Frenkel 1996; Hunt et al. 2011; Boon et al. 2017; Svidrytski et al. 2019; Batany et al. 2019). The presented work is based on measurements and simulations of a sub-REV (Representative Elementary Volume) porous me
Data Loading...
