Numerical Simulation of Melting Process in Single Screw Extruder with Vibration Force Field
Melting capacity is always the bottleneck of performance improvement of single-screw extruder, and become the nodus of the extrusion theory. As a novel extrusion technology, the electromagnetic dynamic plasticating (EMDP) extruder for plastics has acquired great economic and social benefit progressively. But the non-linear viscoelastic behavior of polymer and phase change which is a non-linear problem increase the degree of difficulty of the research on the melting mechanism with vibration force field and restrict the exertion of the potential of EMDP extruder in a degree. In this paper, according to the assumption of “flowing solid”, the hydrokinetics is adopted to solve the whole melting problem region, which solves the phase change and the solid-melt interface tracking problems. A 2D melting model is established. This melting model fits for the research on the influence of vibration force field on the melting process. Since polymer has time-dependent non-linear viscoelastic characteristic with vibration force field, and the melting process is a phase change problem, a user-defined program of self-amended non-isothermal Maxwell constitutive equation is developed with the UPFs of ANSYS. This constitutive equation can reflect the relaxation time spectrum of polymer. The responses of melting process to various vibration parameters are simulated. And the rule of the influence of frequency and amplitude on melting process is analyzed.