In radial flow impregnation of textile preforms, unsaturated experimental studies indicate the presence of an edge flow along the surface of a mold. Instead of a liquid front which is straight and perpendicular to mold surfaces, a complex front profile is observed causing the delayed impregnation in the middle of the preform thickness in comparison with the front position at its surface. This phenomenon becomes of special importance when permeability values are measured by observation of the front at the surface of a mold since they do not represent the impregnation at the mid-plane of the preform leading to errors in permeability measurements. In the past, several theories have been developed to describe the phenomenon of race-tracking. Our study compares theoretical predictions with the experimentally observed data on the width of the front profile. It is found that a crucial role in the formation of the front profile is played by the capillary flow through the thickness of the preform.
- Capillary pressure
- Composite preform
- Edge flow
- Liquid composite molding
- Unsaturated radial injection at constant pressure