2D COMPOSITE MODELS OF MODULAR TANGENTIAL COUNTER-ROTATING TWIN SCREW EXTRUDERS

摘要

A new 2D composite model with hybrid FEM/FDM formulation was developed for simulating the fully filled and starved regions with the associated pressure profiles of a modular tangential counter-rotating twin screw extruder. 1D composite models combine the screw characteristic curve of individual element to analysis flow of an entire modular screw and the flow fields of the whole domain are not calculated again. Based on the linear relationship of the drag flow rate and the screw rotation speed under the single screw extrusion theory, the new mesh with artificial screw rotation speed boundary conditions was used to simulate the entire flow fields for the counter-rotating twin screw extrusion process in our 2D composite models. To demonstrate applicability, the predictions of individual screw elements via hybrid FEM/FDM agree well with Nichols's experimental studies. The pressure and filling factor profiles in a modular LSM34-34 extruder provided by 2D composite models show good agreements with those of 1D composite models.