Problem $6$

An extruder barrel has a diameter $D=75mm.$ The screw rotates at $N=60rpm.$ Channel depth $H=6\mathrm{.}0mm$ and flight angle $=20.$ Head pressure at the end of the barrel $P=7\mathrm{.}0$MPa, length of the barrel $L=1\mathrm{.}9m,$ and viscosity of the polymer melt is assumed to be $=100Pa-s.$ Determine:

the volume flow$-$rate of the plastic in the barrel;

the maximum flow rate $($assuming zero pressure$)$;

the maximum pressure that can be built up in the extruder $($assuming zero output$)$;

the operating pressure $P_{op}$ when a die and $($:$L_d=20(mm)$