Mathematical modeling and numerical simulation for nucleated solution flow through slit die in foam extrusion

Nucleated solution flow models have been previously developed by Baldwin and coworkers to aid modular design of the foam extrusion process. A framework of previously developed design models is applied here to investigate the flow of nucleated polypropylene-CO, solution system. Refinement to the design models is introduced through viscosity reduction factors and Redlich-Kwong equation of state to describe nonideal gas. These models incorporate temperature and concentration dependency of viscosity, surface tension, and solubility. Simulated results of pressure profiles and volumetric flow rates using a power law rheological equation are compared with experimental values from a three pressure tapping slit die. The influence of temperature on the profiles and its effect on design models is discussed. Preliminary results show that temperature plays an important role in the categorization of process design models.