Transfer Coefficients in Spray Cooling of Plastics Pipes [PE]
# 1995 Edinburgh
Heat transfer coefficients for splay cooling in the
manufacture of blue, yellow and black PE-80 and PE100 MDPE pipes are determined by measuring pipe
surface tempemhtres in the annealing zones between
splay tanks, and then fitting a computer simulation of
the cooling process by adjustment of heat wander
coefficients. Data were collected fmm six exhusion
lines producing pipes fmm 63 to 315mm diameter.
T d e r coefficients were found not to depend
simcantly on pipe diameter, or on the variations in
spray arrangements hetween exhusion lines; however, a
si@icant and consistent reduction in values was found
for successive tanks along the cooling line. In the first
(vacuum) tanks a value of about 1500 w/m2 K was
fo\md; in the second 500 w/m2 K and in the third 250
Wlm K. There is no conclusive evidence that polymer
material affects the values, though somewhat higher
mmfer coefficients were deduced for black PE-100.
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