7. Conclusions

One of the fundamental questions of non-uniform heat and mass transfer in viscous fluid was addressed by proposing a radial torsional flow pattern, by designing a torsion element and validating the same in a melt-phase polymer extrusion process. The synergistic interaction mechanisms between velocity and velocity gradient and velocity and temperature gradient have been investigated by considering theoretical and numerical aspects, which provides a new perspective to understand the polymer processing. Considering the multi-field synergy, a new design concept of torsion screw configuration has been proposed to facilitate phaseto-phase thermal and molecular mobility.

The spiral-shaped torsional flow induced by torsion configurations in a polymer channel changes the radial velocity direction, which in turn improves the interaction between velocity and temperature fields and helps to achieve good heat transfer and temperature homogeneity. The new torsion elements and their arrangement provide a novel pathway to achieve good thermal management of polymer melt by enhancing multi-field coupling. These results can be achieved to guide the screw design used for preparing high-performance composites, especially heat-sensible and biodegradable nanocomposites or microcellular foam controlled by temperature.
