Experimental and simulation analysis of capillary impregnation and wettability in cotton fiber porous media

Abstract

Capillary-driven flow is a critical phenomenon in fibrous porous media, influencing a wide range of industrial processes such as filtration, drying, and biomass conversion. Understanding the interplay between material properties and fluid behavior is essential for optimizing these processes. This study aims to analyze capillary flow behavior in cotton fibers by combining numerical simulations with experimental data. An inverse analysis approach was employed to determine several unknown parameters associated with three different liquids: n-heptane, water, and glycerol. Based on simulation data, the wicking velocity of each liquid in the porous medium was calculated, followed by the determination of the corresponding capillary numbers (CA). The results indicate that the capillary numbers for n-heptane, water, and glycerol are 4,91x10-15 ,1,61x 10-15 , and 1,42 x 10-4, respectively, highlighting the differences in infiltration behavior among these fluids. Subsequent simulations systematically examined the effects of porosity, surface tension, and dynamic contact angle on liquid transport . The capillary number was used as a quantitative measure to assess the influence of these parameters on infiltration behavior. Lower Ca values were generally associated with faster liquid absorption, particularly in cases with higher surface tension and smaller contact angles, where capillary forces dominated. This study provides a modeling framework to evaluate parameter effects on capillary flow in fibrous porous media, offering guidance for optimizing materials in filtration and drying applications. It also contributes to a deeper understanding of interfacial transport phenomena in porous structures.