| Extrusion molding is one of the earliest and most wildly used method in polymer processing. As one of the extrusion molding equipment, conical twin-screw extruder is drawing more and more attention. Study on the theory of conical twin-screw extruder is more and more deeply.Three-dimensional modeling of a variety of screw elements used in conical twin-screw extruder were built by SOLID WORKS and meshed by GAMBIT, and the finite elements model was analyzed by POLYFLOW. The pressure field, shear stress field, viscosity field, and velocity field were obtained by static and dynamic simulation. The postprocessing was dealt with FIELDVIEW, with which the volume flow rate, average shear rate, average speed, residencet time distribution and other parameters were acquired.The numerical results showed that the double cone twin screw extruder provide a lower shear stress than the normal cone twin screw extruder; by the comprehensive research on three cross-section screws, it is founded that the acme screw thread provide a lower shear stress.The screw structural parameters, including screw lead, cone angle, the outer cone angle on flow field were simulated and discussed and by the comparison of weighted average and accumulated residenencet time distribution using orthogonal test to analyze the influence on different conical twin-screw structural parameters on product performances, and the optimal parametric combination were obtained.On the basis of the former numerical research, the experiments stuy were carried out by double cone twin screw extruder and normal cone twin screw extruder, it is showed that the product extruded by double cone twin screw extruder present a better performance, the experimental results were in accordanced with the numerical results. |
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