Analyzing the Flow Characteristics of Co-rotating Twin-Screw Extruder Conveying Elements
Sprache des Vortragstitels:
36th International Conference of the Polymer Processing Society
Sprache des Tagungstitel:
Modeling the transport phenomena in fully intermeshing co-rotating twin-screw extruders is key to predicting its processing characteristics. Commonly, it is based on significant geometric simplifications, such as flat plate approximation, and ignoration of flow in the clearances. In this work, we analyzed the conveying characteristics and power consumption of double-flighted fully intermeshing co-rotating twin-screw extruders, taking into account the full three dimensional geometry. First, we transformed the problem into a dimensionless representation and identified its characteristic influencing and target parameters by applying the Buckingham ?-Theorem. Next, we analyzed the fundamental relationships between flow rate, pressure gradient and power requirement, defining suitable conveying and power parameters for a Newtonian fluid. Based on these findings, a comprehensive numerically driven parametric design study was conducted. For each individual modeling setup, the flow field was predicted by means of a full three-dimensional FEM analysis, which was then used to compute the conveying, and power parameters. The numerical results include the influence of screw and nip clearance and hence enable to assess the influence of wear on processing behavior. Additionally, by combining the results of the conveying and power parameters, the viscous dissipation rate and consequently the melt temperature increase can be estimated.