Study on the Effect of Pins on the Flow Field in the Metering Section of Single Screw Extruders

In the present work, attempts were made to study the effect of the presence of pins in the extruder channel on the flow field of the molten polymer in the channel. The flow field of the melt in two pitches of the screw in metering section, with various shapes and arrangements of pins, was simulated and compared with simple screw with no pin using a commercial CFD software, Fluent 6.2.3. It was found that screws with lozenge shaped pins help to achieve higher deformation rates and thus shear stress in the channel. This could lead to have better dispersive performance of the screw compare to simple channel. The presence of dead-spots were studiedThe results showed that pressure drop is related to the number and arrangement of pins. It was also depicted that the presence of pins in extruder channels, in spite of its disadvantages such as enhanced pressure drop, increased the deformation rate and made residence time distribution to become more uniform. It was shown the shape of the pins was the most affecting parameter among the other ones.

کلیدواژه ها:

Single screw extrudr ، Deformation rate ، Dead-spot ، Pressure drop