| The traditional screw extruders has been widely applied to the polymer processing.But in the screw extruder,materiels plasticating and conveying are dominated by shear stress generated by dragging and shear effects.Therefore,there are some inherent drawbacks of this method of polymer materials processing,such as long thermo-mechanical,large size of the equipment,high energy consumption,and strong dependence on material properties.The invention of polymer vane extruder by Jinping Qu, the professor of SCUT,is significant progress in the field of polymer processing method and processing equipment.This invention can solves many problems existing in the screw extruder.The working mechanism of polymer vane extruder was analyzed in this paper. The motion equation of the vane was derived。And physical model of vane extruder were established with the necessary assumption and reasonable simplification.Then3D finite element numerical simulation was performed to investigate the flow in the vane extruder with POLYFLOW.Velocity field,pressure field,local-shear-rate distribution and pressure fluctuation within the vane extruder were analyzed. Finally,the effects of various parameters,such as structural parameters of the vane extruder,rotor speed and melt viscosity,on pressure fluctuation were investigated by performing numerical simulation with different models.The results of numerical simulation revealed that:Shear rate within the vane extruder is generally low.Strong elongational flow can be observed near the export of vane unit.The pressure of flow field shows a ladder-like distribution.and cyclical changes when the rotor rotates.various parameters,such as size of clearance,number of vane,arrangement of vane, arrangement of adjacent unit,rotor speed and melt viscosity,will affect the pressure amplitude, distribution and fluctuation.These studies is very useful to the design and structural optimization of vane extruder,as well as the theoretical study of plasticating and conveying in vane extruder. |
PDF Full Text Request