Mixing analysis of reactive polymer flow in conveying elements of a co-rotating twin screw extruder

Abstract

In this study, the finite element method was used to investigate the effects of screw speed, entering peroxide distribution, and pressure‐to‐drag flow ratio on the mixing characteristics of steady non‐isothermal reactive flows in a forward conveying element of a self‐wiping twin screw extruder. The reaction considered was the peroxide‐initiated degradation of a commodity polypropylene resin. The predicted average degree‐of‐freedom profiles from the simulations largely conformed to expectations. The average flow efficiencies for all runs were found to remain at values close to that for two‐dimensional flow, with fluctuations being observed in the channel intermeshing regions. No significant effect of either screw speed or peroxide distribution was found on the flow efficiencies; however, the pressure‐to‐drag flow ratio was found to have a significant influence. © 2000 John Wiley & Sons, Inc. Adv Polym Techn 19: 22–33, 2000

Analysis of the dispersive mixing efficiency in a twin-screw extrusion processing of starch based matrix

“…To model the flow in an extruder channel containing two rotating intermeshing screws, some type of remeshing or moving-mesh technique is required to take into account the time-dependent volume occupied by the fluid. For this purpose, new meshes for each time-step can be created and time-dependent fields are then obtained by interpolation between these meshes (Bravo et al, 2000;Ishikawa et al, 2000;Strutt et al, 2000;Yang and Manas-Zloczower, 1992). However this meshing task is cumbersome and many meshes or very complex meshing tools are generally required in case of a time-dependent geometry.…”

Visualisation and Analysis of the Flow along the Kneading Block of a Twin-screw Extruder

“…Consequently, two modelling strategies are usually adopted: i) local 3D approaches, which often assume totally filled channels, and are usually computationally demanding (e. g., [2,3]); ii) global 1D or 2D approaches, encompassing the entire process from hopper to die, and adopting simplifications that minimize the computational requirements [4 to 9].…”

Reactive Processing of Thermoplastic Polymers: A Review of the Fundamental Aspects

“…For these reasons, this type of approach is necessarily limited to a small section of the extruder, and to screw elements that are totally filled. Strutt et al [410] investigated the free radical PP degradation in a forward conveying element of an intermeshing co-rotating twin-screw extruder. They used the finite element method to investigate the effects of screw speed, entering peroxide distribution, and pressure-to-drag flow ratio on the mixing characteristics of steady non-isothermal flow in this conveying element.…”