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This paper proposes two important models useful for describing heat transfer and temperature profiles in single and modular self-wiping co-rotating twin-screw extruders. One model predicts heat transfer coefficients. Calculations of the barrel and screw heat transfer coefficients are made for various modules in different diameter extruders. We compare the values of the heat transfer coefficients from the model with those from literature. The second model predicts the axial screw temperature profile when the barrel, but not the screw, is heated, Example calculations of the cup mixing and screw temperature profiles are also made for different diameter extruders.

Extensive experimental studies of a starved flow modular tangential screw extruder are described. Die pressures and fill factor profiles along the screw axis are measured and used to determine screw characteristic curves Q vs. AP/L for individual screw elements of varying designs in a Leistritz twin screw extruder. Superior pumping characteristics of matched as opposed to staggered elements is found. The experimental screw characteristic curves are compared with the results of mathematical simulations of the flow. Agreement is generally good.

A model for flow in a Farrel Continuous Mixer based upon cylindrical coordinate hydrodynamic lubrication theory is presented. Pressure and flux fields over the rotor surface are calculated. The pumping characteristics of the various sections of the machine rotors were calculated. Generally Farrel Continuous Mixers are operated under starved conditions. Calculations are presented for continuous mixers operating under starved conditions. Pressure and fill factor profiles are determined. Fill factors are predicted to be increased by increasing throughput, increasing exit gate pressure and reducing screw speed.