FILM CASTING OF A MODIFIED GIESEKUS FLUID - A STEADY-STATE ANALYSIS

A theoretical analysis of the isothermal steady-state film casting process is conducted. A modified Giesekus rheological model is used in the study. The coupled effects of the rheological model parameters on the velocity profile, the stress profiles, and the film tension are found to be related to the elongational viscosity curve. A positive (negative) slope of the elongational viscosity curve corresponds to a velocity profile above (below) the Newtonian profile. The stress profiles are related to both the magnitude and shape of the elongational viscosity curve. The normalized film tension and the elongational viscosity exhibit strikingly similar characteristics. At high deformation rates, fluids with higher chain extensibility have higher elongational viscosity and require higher film tension; fluids with larger mobility factor have lower elongational viscosity and require lower film tension.