Studies on the numerical simulation of flow fields in the pin barrel extruder

摘要

After structures are simplified and boundary conditions are disposed for the ordinary extruder and the pin barrel extruder with same diameter of 90mm, flow behaviors of rubber materiel by applying FLUENT are studied under the conditions of different rotational speed, different layout of pins and reverse pressure difference. It is shown that the screw flights, grooves of screw flights and pins have great influence on the flow fields, and it is also seen that on cylindrical section with same radius, the velocity gradient and direction change in the pin barrel extruder are rather larger than that of the ordinary extruder. Moreover, the extrusion capacity is in proportion to rotational speed even though the number of pins and the pitch between the two rows of pins are varied, but when the rotational speed is same, conclusions indicate that the longer the pitch between the two rows of pins is and the less the number of pins is, the higher the extrusion capacity is, but the pitch between the two rows of pins has a larger influence on the extrusion capacity. Besides, the extrusion capacity is rather different when there are pins and none of pin, yet the number of pins in each row has little influence on the extrusion capacity. On condition that reverse pressure difference is unchanged, the extrusion capacity is linear with the rotational speed, namely the higher the rotational speed is, the higher the extrusion capacity has. In addition, the extrusion capacity is linear with the reverse pressure difference when the rotational speed is constant, which larger reverse pressure difference leads to lower extrusion capacity. Above research results are very useful when layout of pins and operating parameters of the pin barrel extruder are determined.