Study of residence time distribution in a reciprocating single-screw pin-barrel extruder

Reciprocating single-screw pin-barrel (RSP) extruder is one kind of Buss Kneader type extruders. The purpose of the present paper is to study the residence time distribution (RTD) characteristic in this equipment and the feasibility of the numerical simulation in predicting the RTD. It is well-known that only the macroscopical RTD can be obtained by the experimental study. However, with the help of the numerical simulation, it is possible to get a detailed microcosmic insight on the local flow situation inside the screw. In this study, a digital image processing (DIP) method was used in the experimental study. The RTDs inside the screw elements were simulated using finite element method and the RTD of the whole equipment was assembled by convolution technique. In addition, the effects of the operating conditions on RTD were also analyzed. At last, the reasons that probably caused the difference between the experimental and theoretical results were discussed.