The onset of wall slip and sharkskin melt fracture in capillary flow

1994 ◽  
Vol 34 (19) ◽  
pp. 1441-1449 ◽  
Author(s):  
Savvas G. Hatzikiriakos
Keyword(s):  
Capillary Flow ◽  
Wall Slip ◽  
Melt Fracture

Wall slip and melt-fracture of polystyrene melts in capillary flow

Polymer ◽  
2010 ◽  
Vol 51 (10) ◽  
pp. 2221-2228 ◽  
Author(s):  
Ryohei Komuro ◽  
Koji Kobayashi ◽  
Takashi Taniguchi ◽  
Masataka Sugimoto ◽  
Kiyohito Koyama
Keyword(s):  
Capillary Flow ◽  
Wall Slip ◽  
Melt Fracture

Melt fracture and wall slip of thermoplastic vulcanizates

2020 ◽  
Author(s):  
Nikoo Ghahramani ◽  
Shiling Zhang ◽  
Krishnan Iyer ◽  
Antonios K. Doufas ◽  
Savvas G. Hatzikiriakos
Keyword(s):  
Wall Slip ◽  
Melt Fracture ◽  
Thermoplastic Vulcanizates

Capillary Flow of Yield-Stress Fluids in Microchannels

2006 ◽  
Author(s):  
V. Bertola
Keyword(s):  
Yield Stress ◽  
Flow Regime ◽  
Capillary Flow ◽  
Capillary Tube ◽  
Plug Flow ◽  
Wall Slip ◽  
Critical Distance ◽  
Tube Diameter ◽  
Force Balance ◽  
Theoretical Argument

The wicking of a model yield-stress fluid (hair-gel solution in water) in a capillary tube is studied experimentally. By changing the hair-gel concentration in the solution, the yield stress varied from 5 to 20 Pa. A simple force balance between capillary and viscous forces suggests that the fluid should stop flowing as soon as the wall shear stress reaches the yield value, at a critical distance from the inlet which is independent of the tube diameter. However, this theoretical argument is not confirmed by experiments, which show that the fluid moves well beyond the critical distance determined theoretically, and that there is a well-defined effect of the tube diameter. It is proposed that such behavior may be determined by wall slip, which causes the flow to switch from the Poiseuille flow regime to the plug flow regime.

Wall slip in the capillary flow of molten polymers subject to viscous heating

AIChE Journal ◽  
1997 ◽  
Vol 43 (3) ◽  
pp. 598-608 ◽  
Author(s):  
Eugene E. Rosenbaum ◽  
Savvas G. Hatzikiriakos
Keyword(s):  
Capillary Flow ◽  
Wall Slip ◽  
Viscous Heating ◽  
Molten Polymers

Flow Properties and Melt Distortion in Molten Rubber Compounds under Capillary Extrusion

2013 ◽  
Vol 747 ◽  
pp. 627-630
Author(s):  
Watcharapong Chookaew ◽  
Yanichsa Sukniyom ◽  
Somjate Patcharaphun ◽  
Narongrit Sombatsompop
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Wall Slip ◽  
Skin Layer ◽  
Rubber Compound ◽  
Melt Fracture ◽  
Extrudate Swell ◽  
Rubber Compounds ◽  
Capillary Extrusion

The influences of shear rate and vulcanizing system on the rheological properties and melt fracture of natural rubber compounds were investigated by using a rate-controlled capillary rheometer. The rheological properties of rubber compounds were characterized with respect to the apparent viscosity and extrudate swell. The measured results indicated that the apparent viscosity tended to decrease with increasing shear rate. This was due to the pseudoplastic behavior of molten rubber compound. It was evident that rubber compound using EV system showed the lowest apparent viscosity as compared to those obtained by CV and NS systems, respectively. This was due to the occurrences of premature crosslink at the skin layer and the wall slip of rubber compound during the flow in capillary die. Furthermore, the onset of smooth surface was also observed which depending on the types of crosslink at the skin layer.

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