Résumé
This study evaluates the influence of the liquid properties as well as liquid–fiber interactions on saturated (Ksat) and unsaturated (Kunsat) permeability of a basalt fabric preform. Four test liquids (water, polyethylene glycol, silicone oil and epoxy resin) and two surface natures of fabric (silane based sized and desized) were investigated. The surface properties of silane based and desized basalt fabrics were studied in a previous work. Firstly, the surface and rheological properties of test liquids were characterized. Secondly, saturated and unsaturated in-plane permeability experiments were performed with a pressure difference of 100 kPa. Finally, the capillary pressure , estimated from the ratio Kunsat/Ksat, was related to the ratio between viscous effects and capillary effects and the work of spreading, aiming at improving the understanding of the flow behavior differences observed. Since the velocity is not constant in permeability experiments with an imposed pressure, the modified capillary number (Ca*) is not reliable with these process conditions. Consequently, this ratio was studied without the fluid velocity. The obtained results indicate that, in this study conditions, not only the liquid nature and the fiber surface properties affect the saturated and unsaturated permeability results, but the liquid–fiber interactions must be considered.