Investigation of processing and rheological parameters effect on film blowing process stability by using variational principles

In this study, a numerical stability analysis of the film blowing process is performed. The numerical scheme used is based on a variational principle model of the film blowing operation. This model employs non-isothermal processing conditions, non-Newtonian behavior of the polymer and physically limiting criteria (maximum tensile and/or hoop stress) to investigate the complex relationship between processing conditions (internal bubble pressure, heat transfer coefficient, mass flow rate, cooling air temperature, melt/die temperature), material parameters (extensional viscosity, rupture stress, Newtonian viscosity, flow activation energy, power law index) and film blowing stability