Abstract: Three-dimensional isothermal flows of different screw elements in three-screw extruder were simulated using a polymer analysis package Polyflow. By statistical treatment of numerical results using Fieldview software, the mixing performances of screw elements were characterized and compared in terms of different evaluation methods It was found that the kneading blocks had stronger shearing and stretching actions than other elements, neutral kneading block and left-handed elements had better effect of backflow. Compared with screw thread elements, SME element has weaker shearing capacity, but higher stretching and backflow capacity. The screw elements could reasonably be selected based on the shear sensitivity of the materials in order to improve the quality of the products.

Key words: three-screw extruder, screw element, numerical simulation, mixing characteristics