Modeling of the film blowing process by using variational principles

Variational principles were employed to develop the model describing the formation of the bubble, due to internal bubble pressure and take-up force, in such a way that the resulting bubble shape satisfies the minimum energy requirements. The derived equations for the bubble shape (including HDPE wine-glass shape), take-up force and internal bubble pressure have simple analytical forms with only several physical parameters. The proposed model was used in modeling of the film blowing process for a variety of process conditions and polymer melts taken from the open literature, and a very good agreement between measured and simulated data was found. (C) 2004 Elsevier B.V. All rights reserved.