HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
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Indices:<br />
m: melt<br />
f: melt film<br />
b: barrel<br />
Example with symbols and units<br />
Thermal conductivity Am = 0.174 W/(m <strong>•</strong> K)<br />
Specific heat cpm= 2 kj/(kg <strong>•</strong> K)<br />
Melt density pm = 0.7 g/cm 3<br />
Thermal diffusivity a from Equation 5.47:<br />
a=1.243-10~ 7 m 2 /s<br />
Flight clearance 5pLT =0.1 mm<br />
Screw speed N = 80 rpm<br />
Parameter /J from Equation 5.48:<br />
P= 0.027<br />
For Tf = 137.74 0 C, Tm = 110 0 C and Th = 150 0 C<br />
asz from Equation 5.46:<br />
5.2.2.4 Melt Temperature<br />
The exact calculation of melt or stock temperature can be done only on an iterative basis<br />
as shown in the computer program given in [9]. The following relationships and the<br />
numerical example illustrate the basis of calculating the stock temperature. The result<br />
obtained can only be an estimate of the real value, as it lacks the accuracy obtained by<br />
more exact iterative procedures.<br />
Temperature rise AT:<br />
Heat through the barrel or heat lost from the melt:<br />
(5.49)<br />
(5.50)