extrusion of polyethylene jared stradley chen 4903 december 4, 2006
DESCRIPTION
Overview Project objectives Theory Experimental setup and procedures Results Conclusions and Recommendations References Wrap up Q & ATRANSCRIPT
Extrusion of PolyethyleneJared StradleyCHEN 4903December 4, 2006
Extruders
Overview Project objectives Theory Experimental setup and procedures Results Conclusions and Recommendations References Wrap up Q & A
Project objectives Characterize the flow of
polyethylene in cylindrical die Estimate the maximum flow rate
through a 1” diameter pipe die
Theory Basically, it’s flow through a pipe or
an annulus
Theory cont. Major equations
Pipe flow:
LRPPQ c
8)( 421
drdV
LPPr
2)( 21
More theory Annular flow:
/1ln11
8)( 22
44
21
LRPP
Q
Experimental setup
Experimental procedures Ran polyethylene at 155, 160 and
165 °C at 3, 5, 10 and 15 rpm Collected samples of each run Ran polypropylene at 200, 205 and
210 °C at 3, 5, 10 and 15 rpm Also collected samples Calculated Q, and dv/dr
ResultsShear Stress vs. Velocity Gradient for Polyethylene (pipe flow)
0.0E+00
5.0E+05
1.0E+06
1.5E+06
2.0E+06
2.5E+06
3.0E+06
0 2000 4000 6000 8000 10000 12000
dv/dr (1/s)
τ (Pa
)
155 °C160 °C165 °C
Results cont. Bingham plastic:
o drdV
Results cont.Pressure Drop vs. Velocity for Polyethylene (annulus)
0.00E+00
5.00E+05
1.00E+06
1.50E+06
2.00E+06
2.50E+06
3.00E+06
0.000 5.000 10.000 15.000 20.000 25.000 30.000 35.000 40.000
Velocity (cm/s)
Pres
sure
dro
p (P
a)
155 °C
160 °C
165 °C
Some more resultsPressure drop vs. rpm for polypropylene (pipe flow)
2.00E+06
2.50E+06
3.00E+06
3.50E+06
4.00E+06
4.50E+06
5.00E+06
0 2 4 6 8 10 12 14 16 18
rpm
Pres
sure
dro
p(Pa
)
200 °C
205 °C
210 °C
Maximum pressure drop: 6.40 MPa
Final result
Pressure Drop vs. Velocity for Polyethylene (annulus)
y = 115926x - 318281y = 109967x - 235980
0.00E+00
5.00E+05
1.00E+06
1.50E+06
2.00E+06
2.50E+06
3.00E+06
0.000 5.000 10.000 15.000 20.000 25.000 30.000 35.000 40.000
Velocity (cm/s)
Pres
sure
dro
p (P
a) 155 °C160 °C165 °C
Maximum velocity possible: 59.180 + 4.127 cm/s (95% CI)
Conclusion Polyethylene can be extruded at a
velocity of 59.180 + 4.127 cm/s through a 1” cylindrical pipe die
(95% CI) This result holds for temperatures
between 155 and 165 °C This value compares well with the
industrial flow rate of 0.5 m/s
Recommendations Run both Polyethylene and
Polypropylene at more temperatures Run both at higher rpm Take samples on same day
References Bird, R. B., W. E. Stewart, E. N. Lightfoot.
Transport Phenomena. New York: John Wiley & Sons, 1960.
Ring, T. A. Fundamentals of Ceramic Powder Processing and Synthesis. San Diego: Academic Press, 1996.
de Nevers, N. Fluid Mechanics for Chemical Engineers. New York: McGraw-Hill, 2005.
www.chemfinder.com www.nicodemus.org www.search.com
Wrap up Project objectives Theory Experimental setup and procedures Results Conclusions and Recommendations References
Questions?