Progress Report on Numerical Modeling of Experimental Polymer Melt Flow Behavior.

A combination of experiment and modeling is being used to investigate the effects of material properties on the melt flow behavior of thermoplastics. The dripping behavior of several types of polypropylene has been studied, including measurements of mass loss from the sample and mass collection in the catchpan, surface temperature, and surface velocities. An experimental method was developed for extrapolating viscosity data to high temperatures where bubbles in the polymer make standard rheometry impossible. A finite volume model that uses the volume of fluid method to track the highly distorted interface for a melting and dripping polymer is described. The model includes heat flux to the distorted interface, empirical viscosity as a function of temperature, flow due to gravity, and gasification.