scholarly journals Numerical simulation of residence time, shear rates and throughput in single screw extruders considering wall shear rates

2019 ◽  
Author(s):  
Elmar Moritzer ◽  
Marius Wittke ◽  
Gilmar Heiderich
Keyword(s):  
Numerical Simulation ◽  
Residence Time ◽  
Shear Rates ◽  
Single Screw ◽  
Single Screw Extruders ◽  
Wall Shear ◽  
Screw Extruders

Numerical Simulation of Chaotic Mixing in Single Screw Extruders with Different Baffle Heights

2016 ◽  
Vol 31 (1) ◽  
pp. 108-118 ◽  
Author(s):  
B.-P. Xu ◽  
L. He ◽  
M.-G. Wang ◽  
S.-Z. Tan ◽  
H.-W. Yu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Chaotic Mixing ◽  
Single Screw ◽  
Single Screw Extruders ◽  
Screw Extruders

scholarly journals Properties of Starve-Fed Extrusion on a Material Containing a VHMWPE Fraction

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 944
Author(s):  
Raffael Rathner ◽  
Davide Tranchida ◽  
Wolfgang Roland ◽  
Franz Ruemer ◽  
Klaus Buchmann ◽  
...  
Keyword(s):  
Residence Time ◽  
Time Pressure ◽  
Experimental Studies ◽  
High Viscosity ◽  
Feeding Rates ◽  
Melt Temperature ◽  
Single Screw ◽  
Single Screw Extruders ◽  
Screw Extruders ◽  
Insight Into

Single-screw extruders are usually operated with the screw fully filled (flood-fed mode) and not partially filled (starve-fed mode). These modes result in completely different processing characteristics, and although starve-fed mode has been shown to have significant advantages, such as improved mixing and melting performance, it is rarely used, and experimental studies are scarce. Here, we present extensive experimental research into starve-fed extrusion at feeding rates as low as 25%. We compared various operating parameters (e.g., residence time, pressure build-up, and melting performance) at various feeding rates and screw speeds. The results show a first insight into the performance of starve-fed extruders compared to flood-fed extruders. We explored starve-fed extrusion of a polyethylene material which contains a Very High Molecular Weight Polyethylene fraction (VHMWPE). VHMWPE offers several advantages in terms of mechanical properties, but its high viscosity renders common continuous melt processes, such as compression molding, ram extrusion and sintering, ineffective. This work shows that operating single-screw extruders in extreme starve-fed mode significantly increases residence time, melt temperature, and improves melting and that-in combination—this results in significant elongation of VHMWPE particles.

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