Extruder Principles and Operation

approximately back pressure barrel cooling barrel surface barrel temperatures barrel wall changes channel depth conduction crease decrease depth h diameter dP/dz drag flow effect energy balance enthalpy equation extruder feed pocket film final melt temperature flight clearance flow rate gear pump gel point give greater haul-off heat conduction heat flow Heater power increase limited longitudinal machine maximum mechanical power input melt length melt pumping section Melt temperature Tm melting section mixing Newtonian fluid Non-uniform output Q particles polyethylene polymer pressure flow pressure gradient pseudoplastic Q and pressure Q/Wbh radial ratio reduce screw channel screw cooling screw speed shear heating shear rate shear strain shear stress single-screw extruder solid bed specific power strain energy Table tempera temperature differences temperature gradients temperature profile temperature rise tend thermal thermocouple tion torque transverse ture uniform usually velocity viscosity