Browsing by Author "University of Minnesota Kang Research Group"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Data and numerical simulation setup for Fluid inertia controls mixing-induced precipitation and clogging in pore to network-scale flows
    (2024-01-16) Yang, Weipeng; Chen, Michael; Lee, Sang; Kang, Peter; yang8782@umn.edu; Yang, Weipeng; University of Minnesota Kang Research Group
    Mixing-induced mineral precipitation, a critical process in both natural and engineering processes, presents complex challenges in terms of control and predictability. The dynamics of precipitation, particularly under the influence of fluid flow, remain poorly understood. Using microfluidic experiments and three-dimensional reactive transport simulations, we demonstrate that fluid inertia controls mineral precipitation and clogging at flow intersections, even in laminar flows. We discern distinct precipitation regimes as a function of Reynolds number: low Reynolds numbers (Re ≤ 10) lead to precipitation shut off, whereas high Reynolds numbers (Re ≥ 50) prompt rapid clogging. Additionally, when injection rates are uneven from two inlets, we observed unexpected flow bifurcation phenomena, which resulted in enhanced concurrent precipitation in both downstream channels. Finally, we extend our findings to rough channel intersections and networks and demonstrate that the identified inertial effects that shape precipitation and clogging at the pore scale are also present and even more dramatic at the network scale. The findings provide a framework for designing and optimizing processes in which precipitation is an essential component, as well as shedding light on the fundamental mechanisms governing mixing-induced mineral precipitation in flow systems.
  • Thumbnail Image
    Item
    Numerical simulation setup for single mineral dissolution in a single pore channel
    (2024-01-04) Lee, Woonghee; Kang, Peter; lee02042@umn.edu; Lee, Woonghee; University of Minnesota Kang Research Group
    We conducted pore-scale numerical simulations for single mineral dissolution for two-dimensional and three-dimensional systems using OpenFOAM. We explored the effects of flow rates on mineral dissolution dynamics.
  • Thumbnail Image
    Item
    Numerical simulation setup for variable-density flows in vertical fractures
    (2023-09-07) Cao, Hongfan; Yoon, Seonkyoo; Kang, Peter K; cao00137@umn.edu; Cao, Hongfan; University of Minnesota Kang Research Group
    Fluids with different densities often coexist in subsurface fractures and lead to variable-density flows that control subsurface processes such as seawater intrusion, contaminant transport, and geologic carbon sequestration. In nature, fractures have dip angles relative to gravity, and density effects are maximized in vertical fractures. However, most studies on flow and transport through fractures are often limited to horizontal fractures. Here, we study the mixing and transport of variable density fluids in vertical fractures by combining three-dimensional (3D) pore-scale numerical simulations and visual laboratory experiments. Two miscible fluids with different densities are injected through two inlets at the bottom of a fracture and exit from an outlet at the top of the fracture. Laboratory experiments show the emergence of an unstable focused flow path, which we term a “runlet.” We successfully reproduce an unstable runlet using 3D numerical simulations, and elucidate the underlying mechanisms triggering the runlet. Dimensionless number analysis shows that the runlet instability arises due to the Rayleigh-Taylor instability, and flow topology analysis is applied to identify 3D vortices that are caused by the Rayleigh-Taylor instability. Even under laminar flow regimes, fluid inertia is shown to control the runlet instability by affecting the size and movement of vortices. Finally, we confirm the emergence of a runlet in rough-walled fractures. Since a runlet dramatically affects fluid distribution, residence time, and mixing, the findings in this study have direct implications for the management of groundwater resources and subsurface applications.
  • Thumbnail Image
    Item
    Scripts for flow and transport in discrete fracture networks and dead-end fracture identification
    (2023-02-22) Yoon, Seonkyoo; Hyman, Jeffrey D.; Han, Weon Shik; Kang, Peter K.; yoonx213@umn.edu; Yoon, Seonkyoo; University of Minnesota Kang Research Group
    Script files for flow and transport simulation using dfnWorks are included. In addition, a MATLAB code for dead-end fracture identification is included.