Permeability Impact on the Pressure Rise in a Pultrusion Die

Abstract

The pressure rise in a pultrusion die inlet can have a significant impact on the quality of a pultruded product; therefore, a model to predict the pressure rise would be a very useful and effective tool for enhancing the pultrusion process and the pultruded product. There are several parameters that can strongly affect the pressure rise in the pultrusion die inlet. One particular parameter is the permeability. In this study, three permeability models are employed to investigate their effect on the pressure rise in the pultrusion die inlet. A numerical model, based on Darcy's law for flow in a porous media that employs the finite volume solution method, is developed to predict the pressure and velocity fields in the pultrusion die. The numerical results are compared with some preliminary experimental data for both glass and graphite composites to determine which permeability model agrees best with the data. An effective fiber diameter is introduced to account for nonuniform fiber diameters and nonuniform spatial fiber distributions.