WETTING OF FIBER MATS FOR COMPOSITES MANUFACTURING .2. AIR ENTRAPMENTMODEL

In this work the experimental observations are explained with the aid of a simple air-entrapment model based on the concept of two levels of porosity of fiber mats, A simple model that includes liquid bypassing with initial air trapping, subsequent capillary invasion of regular f iber bundles with air compression, and finally mobilization is propose d to explain air-entrapment phenomena. The simple model successfully r ationalizes the observed air trapping and compression during initial l iquid-fiber contact. An empirical equation for the mobilization effici ency is adapted to the model to estimate void content. The velocity de pendence of the trapped void content predicted by the model is in good agreement with observations.