Capillary Filling at the Microscale: Control of Fluid Front Using Geometry.
We propose an experimental and theoretical framework for the study of capillary filling at the micro-scale. Our methodology enables us to control the fluid flow regime so that we can characterise properties of Newtonian fluids such as their viscosity. In particular, we study a viscous, non-inertial, non-Washburn regime in which the position of the fluid front increases linearly with time for the whole duration of the experiment. The operating shear-rate range of our apparatus extends over nearly two orders of magnitude. Further, we analyse the advancement of a fluid front within a microcapillary in a system of two immiscible Newtonian liquids. We observe a non-Washburn regime in which the front can accelerate or decelerate depending on the viscosity contrast between the two liquids. We then propose a theoretical model which enables us to study and explain both non-Washburn regimes. Furthermore, our theoretical model allows us to put forward ways to control the emergence of these regimes by means of geometrical parameters of the experimental set-up. Our methodology allows us to design and calibrate a micro-viscosimetre which works at constant pressure.
Departament ECM, Facultat de Física, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona, Spain.|Centre de Recerca Matemàtica, Edifici C, Campus de Bellaterra, 08193 Bellaterra (Barcelona), Spain.
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Trejo-Soto
Centre de Recerca Matemàtica, Edifici C, Campus de Bellaterra, 08193 Bellaterra (Barcelona), Spain.|Departament de Matemàtiques, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain.|Barcelona Graduate School of Mathematics (BGSMath), Barcelona, Spain.
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Costa-Miracle
Centre de Recerca Matemàtica, Edifici C, Campus de Bellaterra, 08193 Bellaterra (Barcelona), Spain.
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Rodriguez-Villarreal
Servicio de Hemoterapia y Hemostasia, Hospital Clínic de Barcelona, Barcelona, Spain.
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Cid
ICREA (Institució Catalana de Recerca i Estudis Avana̧ts), Barcelona, Spain.|Centre de Recerca Matemàtica, Edifici C, Campus de Bellaterra, 08193 Bellaterra (Barcelona), Spain.|Departament de Matemàtiques, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain.|Barcelona Graduate School of Mathematics (BGSMath), Barcelona, Spain.
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Alarcón
Departament ECM, Facultat de Física, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona, Spain.|Centre de Recerca Matemàtica, Edifici C, Campus de Bellaterra, 08193 Bellaterra (Barcelona), Spain.|Barcelona Graduate School of Mathematics (BGSMath), Barcelona, Spain.
Aurora
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Hernández-Machado
D008962:Models, Theoretical; D014783:Viscosity