Thermosoftening Plastics

polyethylene, and polyurethane.). Therefore, we assume modeling and simulated results based on the above conditions, which are generally applicable for most of the materials used in polymer processing.

progressively refined meshes for the screw and fluid models were constructed to ensure that the simulation results were mesh-independent. Different screws had the same mesh refinement setting and, with the same fluid model, simulation results were displayed in the grid of fluid domain. Table 4 gives the flow and thermal

Multi-Field Synergy Process for Polymer Plasticization: A Novel Design Concept for Screw…

Firstly, we investigated the axial melt temperature distribution by selecting different radial reference lines for these six screws as shown in Figure 5. From all the six screws, we can find that the temperature fluctuations decrease by the effect of torsion elements and the temperature difference between melt and barrel wall in the position of torsion elements is smaller than that of the position of screw elements. The reason for this phenomenon is heat transfer enhancement caused by the synergy effect between velocity and temperature gradient. We will prove this in the next section. Figure 6 shows the radial melt temperature distribution for screw B in the position of torsion and screw elements. For the position of torsion element, almost all the fluid is in a high-temperature region, more than 500°C, while the radial temperature for most fluid in the screw channels is below 500°C. Results indicated that the radial temperature difference in the position of torsion element is much lower compared with that of the position of screw elements, no matter before

Radial and axial temperature distribution for the different screws at 40 r/min. (1) r = 14.5 mm;

Temperature contours (left) and melt temperature profiles (right) across the melt flow with the magnitude of

(2) r = 14.0 mm; (3) r = 13.5 mm; (4) r = 13.0 mm.

fluctuations for screw B at different x-positions at 40 r/min.

boundary conditions used in this case.

DOI: http://dx.doi.org/10.5772/intechopen.89616

5. Results and discussion

5.1 Temperature uniformity

Figure 5.

Figure 6.

25

In our work, ANSYS Polyflow 17.0 packaged software (ANSYS, Inc.) was adopted in the simulations. The 3D mesh systems for the screw and the fluid were created using the mesh superposition technique (MST). Figure 4 shows the 3D model for screw E. The fluid model and screw model were implemented through mesh refinement by hexahedral and tetrahedral elements, respectively. In addition,


#### Table 2.

Physical parameters of the PP.


#### Table 3.

Physical parameters of the screw.

#### Figure 4.

Three-dimensional physical model of screw E.


#### Table 4. Boundary conditions.

Multi-Field Synergy Process for Polymer Plasticization: A Novel Design Concept for Screw… DOI: http://dx.doi.org/10.5772/intechopen.89616

progressively refined meshes for the screw and fluid models were constructed to ensure that the simulation results were mesh-independent. Different screws had the same mesh refinement setting and, with the same fluid model, simulation results were displayed in the grid of fluid domain. Table 4 gives the flow and thermal boundary conditions used in this case.
