3-DIMENSIONAL FINITE-ELEMENT ANALYSIS OF POLYMER ROTATIONAL EXTRUSION

A three-dimensional finite element approach has been employed to model steady, creeping, isothermal helical flows and to study the effect of an imposed rotational field in a wire coating process and a tube extr usion process. It has been shown that the rotational field can affect process characteristics with an underlying viscous character, such as the velocity profile, pressure drop, viscous extrudate swelling, mater ial pathlines, and deformation field. Significant pressure drop reduct ion may be achieved with implications on the process productivity, pre ssure drop reduction being most prevalent at low power-law indices bec ause of the increased nonlinearity in the shear-thinning viscosity fun ction. Extrudate swelling has been shown to be affected by the rotatio nal field owing to the shear-thinning nature of polymeric materials. F inally, it has been shown that significant material deformation may re sult from the imposition of the rotational field.