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Naret Intawong . Examinations of radial extrudate swell and velocity profiles of a flowing polystyrene melt in extrusion processes. Doctoral Degree(Materials Technology). King Mongkut's University Technology Thonburi. Library. : King Mongkut's University of Technology Thonburi, 2004.
Examinations of radial extrudate swell and velocity profiles of a flowing polystyrene melt in extrusion processes
การตรวจสอบพฤติกรรมการบวมตัวและรูปแบบการไหลเชิงรัศมีของพอลิสไตรีนหลอมเหลวในกระบวนการอัดรีด
Name: Naret Intawong
Organization :
King Mongkut's University of Technology Thonburi. School of Energy, Environment and Materials. Materials Technology
keyword:
Extrudate swell
Abstract:
This thesis aimed to investigate the radial extrudate swell and velocity profiles of polystyrene (PS) melt in a capillary die of a constant shear-rate extrusion rheometer and a single screw extruder, using a novel technique called "A Parallel Co-extrusion Technique, (PCT)", which was specially designed and manufactured in this work. An electromagnetizedcapillary die was constructed and used to investigate the effect- of the magnetic field on the radial extrudate swell and velocity profiles of the PS melt flowing in the capillary die. Furthermore, effect of magnetic field on the extrudate swell for different die materials (steel and stainless) was studied.For a normal die ( without applying the magnetic field ) in the capillary rheometer and single screw extruder, the experimental results suggested that the overall extrudate swell for all shear rates decreased with increasing die temperature, and appeared to increase with increasing shear rate to the maximum swell about 8.5 i l , and then decreased with higher shear rate (17.1 s-') For radial extrudate swell and velocity profiles, it was found that the extrudate swell profiles were closely linked with the development of the velocity profiles of the melt in the die. The extrudate swell ratio was high at the die center and low near the die wall, and the extrudate swell ratio at the qie center of the die reduced slightlyas the shear rate increased. Variations in radial extrudate swell profiles were explained in terms of changes in melt velocity, shear rate, and resident time at radial positions across the die.For an electro-magnetic die (applied with the magnetic field) in the capillary rheometer and single screw extruder, the experimental results suggested that the overall extrudate swell for all shear rates increased with increasing magnetic flux density to a maximum value and then decreased at higher densities. The maximum swelling peak of the melt appeared to shift to higher magnetic flux density, and the value of the maximum swell decreased with increasing wall shear rate and die temperature. The effect of magnetic torque on the extrudate swell ratio of PS melt was more pronounced when the melt was extruded at low shear rates and low die temperatures. For radial extrudate swell and profiles, the radial swell ratio for a given shear rate decreased with increasing r/R position. There were two regions where the changes in the extrudate swell ratio across the die diameter were obvious with changing magnetic torque and shear rate, one around the duct centre and the other around r/R of 0.65-0.85. The changes in the extrudate swell profiles across the die diameter were associated with, and can be explained by using the melt velocity profiles generated during the flow. When comparing the swell level of PS melt from the capillary rheometer and single screw extruder, the experimental results suggested that the extrudate swell ratio of the single screw extruder was higher than that the capillary rheometer approximately 20 % for overall swell and approximately 30-55 % for radial swell. This opposite effect was found when using the electromagnetic die.Finally, it was observed that the overall extrudate swell ratios from the steel die were higher than those from stainless die, approximately 10 % for the measurement without magnetic fields. Upon application of the magnetic field, using steel die caused an increase in extrudate swell ratio, while using stainless die resulted in a decrease in extrudate swell ratio.
King Mongkut's University Technology Thonburi. Library
Address:
Bangkok
Email:
info.lib@mail.kmutt.ac.th
Name: Narongrit Sombatsompop
Role:
Advisor
Created:
2004
Issued:
2007-07-23
Modified:
2014-02-07
วิทยานิพนธ์/Thesis
ISBN:
9741841256
CallNumber:
MT241
eng
DegreeName: Doctor of Philosophy
Level: Doctoral Degree
Descipline: Materials Technology
©copyrights King Mongkut's University of Technology Thonburi
RightsAccess:
ใช้เวลา
0.029995 วินาที
Naret Intawong
| Title | Contributor | Type |
|---|---|---|
| Examinations of radial extrudate swell and velocity profiles of a flowing polystyrene melt in extrusion processes
มหาวิทยาลัยเทคโนโลยีพระจอมเกล้าธนบุรี Naret Intawong | Narongrit Sombatsompop | วิทยานิพนธ์/Thesis |
Narongrit Sombatsompop