DISTRIBUTED MODEL OF FLOW IN SPIRAL MANDREL DIE.

Spiral mandrel dies are widely employed in the processing of polymeric films in the blown extrusion process. The flow dynamics in spiral mandrel dies is modeled in conjunction with a lubrication assumption. The model permits the determination of velocity, rate of deformation, shear stress, and first normal stress difference distributions. It should generate a better understanding of the thermomechanical history experienced by polymeric melts during extrusion in spiral mandrel dies, and should thus facilitate better die design and/or optimization of operating conditions.