Melt Flow 1
1
Melt Flow in Extruder As screw rotates inside barrel, polymer melt is forced to move forward toward die; as in an Archimedean screw Principal transport mechanism is drag flow (Q d ) resulting from friction between the viscous liquid and the rotating screw Compressing the polymer melt through the die creates a back pressure that reduces drag flow transport (called back pressure flow, Q b ) Resulting flow in extruder is Q x = Q d – Q b Q d = Volume drag flow rate (m 3 /s) Q b = back-pressure flow rate (m 3 /s)
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Transcript of Melt Flow 1
Melt Flow in Extruder
As screw rotates inside barrel, polymer melt is forced to move forward toward die; as in an Archimedean screw
Principal transport mechanism is drag flow (Qd) resulting from friction between the viscous liquid and the rotating screw
Compressing the polymer melt through the die creates a back pressure that reduces drag flow transport (called back pressure flow, Qb )
Resulting flow in extruder is Qx = Qd – Qb Qd = Volume drag flow rate (m3/s) Qb = back-pressure flow rate (m3/s)