摄动环异向双螺杆挤出特性及分散混合数值模拟研究OA

In order to improve the mixing performance of CRDS and reduce the calendering effect while maintaining the positive displacement effect,a perturbation-ring counter-rotating double screw(PRCRDS)is proposed.With the help of SOLIDWORKS software,physical models of counter-rotating double screw are constructed respectively for non-intermeshing counter-rotating double screw(NCR),counter-rotating double screw(CR),and perturbation-ring counter-rotating double screw(PRCR).ICEM CFD software is applied to perform meshing.Subsequently,the finite element method(FEM)provided by POLYFLOW software and its mesh superposition technology(MST)are used to analyze the transient simulation of three configurations of twin-screw extrusion process under isothermal conditions using the Bird-Carrreau constitutive model,and to investigate the dynamic changes of the flow field,the flow field of different screw configurations in the extrusion process.The dynamic changes of flow field,pressure establishment capacity and mixing effect under different screw configurations are investigated in depth.The numerical results show that PRCR exerts a stretching effect on the co-mingled material with one-third of the screw force of the CR,which reduces the original calendering effect existing in CR,and improves the mixing performance of the extruder,because the stretching effect brought about by the cyclic change of the depth of the screw groove acts synergistically with the shear effect,which further optimizes the distribution of mixing effect.Under the same processing conditions,the residence time distribution of PRCR is between that of NCR and CR,with an average residence time up to 1.6 times higher than that of the remaining two,and the results of the mixing index can illustrate that its axial mixing performance of the particles has been significantly improved.