REFERENCES: 1. Kunz P., Zarikos I.M., Karadimitriou N.K., Huber M., Nieken U., Hassanizadeh S.M., Transport in Porous Media, 114, 581-600 (2015) 2. Karadimitirou N.K., Musterd M., Kleingeld P.J., Kreutzer M.T., Hassanizadeh S.M., Joekar- Niasar V., Water Resources Research, 49, 2056-2067 (2013) Pore-Scale Modeling of Immiscible Two-Phase Flow in Predominantly 2D Microfluidic Porous Domains A. Dollari 1 , A.G. Yiotis 1,* , I. Zarikos 2 , N. Karadimitriou 3 & S. M. Hassanizadeh 2 1. Environmental Research Laboratory, NCSR “Demokritos”, Athens, Greece, 2. Environmental Hydrogeology Group, Utrecht University, The Netherlands, 3. Institute of Mechanics, University of Stuttgart, Germany Email: yiotis@ipta,demokritos.gr We study the dynamics of immiscible two-phase flow in a microfluidic device that consists of randomly distributed cylindrical obstacles to “mimic” flows within the tortuous space of macroporous geological porous media (e.g. soils, fractured rocks etc). The flow problem is solved in a reduced-order 2D computational domain using the Level-Set method, assuming a negligible effect of domain’s depth on the interfacial dynamics and a fixed contribution of the z- direction on the capillary pressure drop across the interface. The computational results are then compared to experimental results obtained using an actual 3 D microfluidic device by the Enviromental Hydrogeology Group of Utrecht University Introduction The microfluidic device is of size 2 .5 x 1.0mm 2 (central area) and depth 0.1mm. The device is initially saturated by Fluorinert (wetting fluid, ρ=1800kg/m 3 , μ=4.7 mPa*s) and died water (ρ=1000kg/m 3 , μ=1 mPa*s) is injected from the inlet channel (0.5mm x 0.1mm cross-section, 2.5mm long) Contact angle 45˚, interfacial tension 55mN/m. Experimental Setup Experimental Result, ΔP=1860Pa Simulations, ΔP=2290Pa Initially, we employ the Laminar flow Physics Interface of COMSOL Multiphysics® in the actual 3D device (2.5 x 1.0 x 0.1mm 3 ) using the Inflow/ Outflow approximation in the 2.5mm inlet/outlet channels to compare flow rates for fixed ΔΡ Single phase flow 3D simulations ΔP=1860Pa Qexp=0.32ml/min Qsim=0.41ml/min From capillarity to viscous-controlled 2-phase flow t=6ms t=36ms t=52ms t=96ms t=50ms t=850ms t=1250ms t=1450ms Viscosity-controlled pattern Capillarity-controlled pattern = / Capillary Number = Viscous/Capillary forces Water saturation vs time for various fixed flow rates Inlet reservoir pressure in the capillary regime, q=1.5e -2 ml/min • Efficient description of 2-phase flow dynamics using both Level-set and Phase-field interfaces • Saturation profiles compare very well with experimental results • Differences in actual time scale could be due to order reduction (3D -> 2D) and microroughness Results-Discussion We employ the coupled Level-Set and Laminar flow Physics interfaces to solve for immiscible 2-phase flow in a simplified 2D domain. Assumptions : • Constant wetting angle θ=0.2π, Fixed ΔP • Fixed capillary pressure drop due to the depth • Shallow channel approximations for viscous flow 2-phase flow 2D simulations- Comparison w. Experiments Excerpt from the Proceedings of the 2018 COMSOL Conference in Lausanne

Pore-Scale Modeling of Immiscible Two-Phase Flow in ... · Single phase flow 3D simulations ΔP=1860Pa Qexp=0.32ml/min Qsim=0.41ml/min From capillarity to viscous-controlled 2-phase

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Page 1: Pore-Scale Modeling of Immiscible Two-Phase Flow in ... · Single phase flow 3D simulations ΔP=1860Pa Qexp=0.32ml/min Qsim=0.41ml/min From capillarity to viscous-controlled 2-phase

REFERENCES:1. Kunz P., Zarikos I.M., Karadimitriou N.K., Huber M., Nieken U., Hassanizadeh S.M.,

Transport in Porous Media, 114, 581-600 (2015)2. Karadimitirou N.K., Musterd M., Kleingeld P.J., Kreutzer M.T., Hassanizadeh S.M., Joekar-

Niasar V., Water Resources Research, 49, 2056-2067 (2013)

Pore-Scale Modeling of Immiscible Two-Phase Flow in Predominantly 2D Microfluidic Porous Domains

A. Dollari1, A.G. Yiotis1,*, I. Zarikos2, N. Karadimitriou3 & S. M. Hassanizadeh2

1. Environmental Research Laboratory, NCSR “Demokritos”, Athens, Greece, 2. Environmental Hydrogeology Group, Utrecht University, The Netherlands, 3. Institute of Mechanics, University of Stuttgart, Germany

Email: yiotis@ipta,demokritos.gr

We study the dynamics of immiscible two-phase flowin a microfluidic device that consists of randomlydistributed cylindrical obstacles to “mimic” flowswithin the tortuous space of macroporous geologicalporous media (e.g. soils, fractured rocks etc). Theflow problem is solved in a reduced-order 2Dcomputational domain using the Level-Set method,assuming a negligible effect of domain’s depth on theinterfacial dynamics and a fixed contribution of the z-direction on the capillary pressure drop across theinterface. The computational results are thencompared to experimental results obtained using anactual 3D microfluidic device by the EnviromentalHydrogeology Group of Utrecht University

IntroductionThe microfluidic device is of size 2.5 x 1.0mm2 (centralarea) and depth 0.1mm. The device is initiallysaturated by Fluorinert (wetting fluid, ρ=1800kg/m3,μ=4.7 mPa*s) and died water (ρ=1000kg/m3, μ=1mPa*s) is injected from the inlet channel (0.5mm x0.1mm cross-section, 2.5mm long)

Contact angle 45˚, interfacial tension 55mN/m.

Experimental Setup

Experimental Result, ΔP=1860Pa Simulations, ΔP=2290Pa

Initially, we employ the Laminar flow PhysicsInterface of COMSOL Multiphysics® in the actual 3Ddevice (2.5 x 1.0 x 0.1mm3) using the Inflow/ Outflowapproximation in the 2.5mm inlet/outlet channels tocompare flow rates for fixed ΔΡ

Single phase flow 3D simulations

ΔP=1860Pa

Qexp=0.32ml/min

Qsim=0.41ml/min

From capillarity to viscous-controlled 2-phase flow

t=6

t=3

st=

t=9

t=5

st=

t=1

Viscosity-controlled pattern

Capillarity-controlled pattern

𝐶𝑎 = 𝜇𝑢/𝛾

Capillary Number = Viscous/Capillary forces

Water saturation vs time for various fixed flow rates

Inlet reservoir pressure in the capillary regime, q=1.5e-2 ml/min

• Efficient description of 2-phase flow dynamicsusing both Level-set and Phase-field interfaces

• Saturation profiles compare very well withexperimental results

• Differences in actual time scale could be due toorder reduction (3D -> 2D) and microroughness

Results-Discussion

We employ the coupled Level-Set and Laminar flowPhysics interfaces to solve for immiscible 2-phaseflow in a simplified 2D domain.Assumptions:• Constant wetting angle θ=0.2π, Fixed ΔP• Fixed capillary pressure drop due to the depth• Shallow channel approximations for viscous flow

2-phase flow 2D simulations-Comparison w. Experiments

Excerpt from the Proceedings of the 2018 COMSOL Conference in Lausanne