The influence of the axial pressure gradient on flow rate for Newtonian liquids in a self wiping, co-rotating twin screw extruder

1980 ◽  
Vol 20 (14) ◽  
pp. 965-971 ◽  
Author(s):  
C. D. Denson ◽  
B. K. Hwang
Keyword(s):  
Pressure Gradient ◽  
Flow Rate ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Axial Pressure ◽  
Axial Pressure Gradient ◽  
Twin Screw ◽  
Newtonian Liquids

Numerical Simulation of Effect of Slip Conditions on PVC Co-Rotating Twin-Screw Extrusion

2011 ◽  
Vol 189-193 ◽  
pp. 1946-1954 ◽  
Author(s):  
Ying Han Cao ◽  
Jin Nan Chen
Keyword(s):  
Flow Rate ◽  
Volumetric Flow Rate ◽  
Wall Slip ◽  
Slip Condition ◽  
Twin Screw Extruder ◽  
Slip Coefficient ◽  
Twin Screw Extrusion ◽  
Screw Extruder ◽  
Slip Conditions ◽  
Twin Screw

The effect of wall conditions on the co-rotating parallel twin-screw extrusion of rigid polyvinyl chloride (RPVC) is studied. The relationship between the shear stress at the screw wall and the slip velocity of the flowing melt obeys Navier’s linear law. At zero pressure difference between the entrance and exit of the melting section of twin-screw extruder, the volumetric flow rate and 3D isothermal flow fields of RPVC are calculated under different wall slip conditions in the metering section of the twin-screw extruder by using the evolution technique in POLYFLOW. The results show that when the slip coefficient is smaller than 104Pa*s/m , the volumetric flow rate of the melt is constant, corresponding to the full slip condition. When the slip coefficient is larger than 104Pa*s/m , with the slip coefficient decreasing, the volumetric flow rate and viscosity increase, but the gradients of velocity, pressure, and shear rate decrease. The residual stress of the product is thus reduced. Therefore, increasing wall slip is good for the stability of polymer extrusion and the product quality. The dispersive and the distributive mixing of the twin-screw extruder under full slip and no slip conditions are also studied. Results show that the mixing performance under no-slip condition is better than under full-slip condition, but slip at the wall is good for the extrusion of heat-sensitive materials.

scholarly journals Experimental and Numerical Simulation Study of Devolatilization in a Self-Wiping Corotating Parallel Twin-Screw Extruder

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2728
Author(s):  
Masatoshi Ohara ◽  
Yuya Sasai ◽  
Sho Umemoto ◽  
Yuya Obata ◽  
Takemasa Sugiyama ◽  
...  
Keyword(s):  
Surface Area ◽  
Flow Rate ◽  
Volatile Component ◽  
Volatile Components ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Surface Renewal ◽  
Twin Screw Extruders ◽  
Renewal Model ◽  
Twin Screw

Devolatilization is an important process for separating and removing unnecessary residual volatile substances or solvents during the production of polymers using twin-screw extruders. Latinen proposed a surface renewal model to determine the concentration of volatile components in the extrudate of a single-screw extruder. When a twin-screw extruder is used to calculate the concentration, it is necessary to use the exposed surface area of the resin in the starved region of Latinen’s model, which, however, is difficult to estimate. In our previous work, we numerically determined resin profiles of the screws using the 2.5D Hele–Shaw flow model and the finite element method, which helps in estimating the surface area of devolatilization. In this study, we numerically analyzed the volatile concentration of the extrudate in a self-wiping corotating twin-screw extruder using Latinen’s surface renewal model along with our resin profile calculation method. The experimental results of the concentrations of the volatile component (toluene) in the extrudate of polypropylene agreed well with its numerical calculation with a relative error of 6.5% (except for the data of the lowest rotational speed). Our results also showed that decreasing the flow rate and increasing the pump capacity were effective for removing the volatile component. The screw pitch of a full-flight screw was not affected by the devolatilization efficiency with a fixed flow rate and screw speed.

Reactive Blending in a Twin Screw Extruder

1996 ◽  
Vol 11 (2) ◽  
pp. 139-146 ◽  
Author(s):  
A. De Loor ◽  
P. Cassagnau ◽  
A. Michel ◽  
L. Delamare ◽  
B. Vergnes
Keyword(s):  
Twin Screw Extruder ◽  
Reactive Blending ◽  
Screw Extruder ◽  
Twin Screw

SME-Arrhenius Model for WSI of Rice Flour in a Twin-Screw Extruder

2005 ◽  
Vol 82 (5) ◽  
pp. 574-581 ◽  
Author(s):  
Hanwu Lei ◽  
R. Gary Fulcher ◽  
Roger Ruan ◽  
Bernhard van Lengerich
Keyword(s):  
Rice Flour ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Arrhenius Model ◽  
Twin Screw
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