Investigation of vortex development during polymer melt flows by flow birefringence

Abstract

The vortex development of low-density polyethylene Lupolen 1840H polymer melt under various processing conditions has been investigated by flow induced stress birefringence technique. It has been revealed that effect of mass flow rate and temperature on the vortex size has non-monotonic character, which is in good agreement with laser-Doppler velocimetry based measurements reported for the same polymer in the open literature. This suggests that the flow induced stress birefringence technique can be considered as the quick and reasonably precise tool for vortices shape/size visualization and quantification at the slit die entry region.