Inscrição na biblioteca: Guest
Início Arquivos Representantes Futuras reuniões American Society of Thermal and Fluids Engineering


Juan I. Ramos
Escuela de Ingenierias Industriales, Universidad de Malaga, Dr. Ortiz Ramos, s/n 29071 Malaga, Spain

DOI: 10.1615/TFESC1.fnd.012994
pages 985-999

Palavras-chave: Film drawing, polymers, molecular orientation, crystallization, solidification


A two-dimensional model for the drawing of incompressible, liquid semi-crystalline, incompressible polymer films that accounts for the molecular orientation and the crystallization of the polymer macromolecules and the heat exchanges with the surrounding gases is presented. The model employs a mixed rheology that includes both Newtonian and polymeric contributions, where the dynamic viscosity of the Newtonian rheology depends on the temperature through an Arrhenius expression, the degree of molecular orientation and the degree of crystallization, whereas the polymeric contribution depends on the molecular orientation tensor, the temperature and a relaxation time which, in turn, depends on the temperature. Heat exchanges with the surroundings have been modelled by means of a heat transfer correlation that includes natural and forced convection and radiation. The nonlinearly coupled governing equations of the two-dimensional model have been solved numerically in two transformed domains by means of a finite volume technique and a domain-decomposition procedure. It is shown that the temperature and degree of crystallization are not uniform across the film, and that full molecular orientation is achieved close to the die's exit, whereas full crystallization is not achieved at the chill roll where the film is collected. It is also shown that forced convection is more important than natural convection and radiation for cooling gases flowing from the chill roll towards the die's exit, while natural convection is smaller than radiation for vertical films in the absence of forced convection.

Compra $20.00 Check subscription Ética e negligência em publicaçãoes Recomendado ao My Librarian Inserir indicador nessa página