BECAS
GERLERO Gabriel Santiago
congresos y reuniones científicas
Título:
A wetting front generator for the assessment of capillarity models based on the Richards equation
Autor/es:
GABRIEL S. GERLERO; RAÚL URTEAGA; CLAUDIO L. A. BERLI; PABLO A. KLER
Lugar:
Córdoba
Reunión:
Congreso; II Brazil-Argentine Microfluidics Congress; 2019
Resumen:
The Richards equation describes the flow of liquids in unsaturated porous media. The advantages of this equation over the Lucas-Washburn equation include the representation of the continuous distribution of liquid in the domain, its applicability to arbitrary ge- ometries, and the ability to extract continuous velocity fields for the transport of solutes such as analytes or reactives. The Richards equation has been employed in simulations of imbibition of paper-based microfluidic devices with controversial results, due mainly to the difficulty in studying and characterizing the most common porous substrates used in paper-based microfluidics. The main issue in this characterization stems from the differ- ent natures of the measurable properties of the substrates and the capillary pressure and permeability (capillarity) models required by the Richards equation. In order to facilitate this complex but critical process, we have developed a software toolbox that covers the use of the Richards equation in a lateral flow setup, where the porous medium may be defined by arbitrary capillarity models. The toolbox features a wetting front generator, which can quickly predict the continuous saturation and velocity fields, and thus enables the study and validation of capillarity models in an efficient manner. In an effort to obtain better models for paper substrates and to showcase its utility in paper-based microfluidics, we have used the developed software to study experimental data both from the literature and our own experiments. The work lays the groundwork for the development of new modelsand their validation in the near future.