Study On The Rheological Properties Of Polyester Melt And Its Influence On The Flow Field In The Spinning Pack

In the fiber production process,melt spinning has the advantages of simple equipment,less investment and excellent performance of the processed fiber,etc.It is very popular;in the spinning process,the polymer melt is extruded into filaments through the spinning pack Strip is the most important process in the fiber forming process.The spinning pack is mainly composed of sand chamber,distribution plate,spinneret,etc.The ideal spinning pack should be able to ensure that the residence time of the polymer melt in the assembly is consistent,and the melt can be uniformly discharged from the spinneret hole Medium extrusion,and many of the current components have uneven filaments,broken filaments,etc.,which requires us to conduct in-depth research on the flow field in the spinning components.In this paper,starting from the rheological properties of polymers,by consulting the literature,it can be seen that most of the spinning melts are pseudoplastic fluids.At the same time,the rheological properties of different polyester melts at spinning temperature are obtained through rheological experiments.The law equation can fit the rheological properties of polymer melts well.The flow of fluid in the spinning assembly can be regarded as the combined flow of fluid in multiple flat plates and circular tubes;therefore,the numerical simulation results of power-law fluids in simple structures of circular tubes and flat plates are compared with their analytical solutions,and the numerical simulation results are found The analytical solution can be well matched.Secondly,the simulation results of the drag flow in the square cavity are compared with the results in the literature.It is found that the simulation results are in good agreement with the data in the literature;this can theoretically explain the correctness of the numerical simulation.Afterwards,a civil silk spinning component used by the China Textile Institute was used as a model to simulate the internal flow field of the component.Through simulation,it was found that the consistency coefficient K in the power law model has a greater impact on the inlet pressure of the spinning component.The internal velocity distribution has a small effect.The non-Newtonian index n has a greater impact on the pressure and velocity distribution of the component.As the non-Newtonian index n increases,the pressure at the inlet of the spinning component will also increase.The stagnation area in front of the spinneret in the assembly will be reduced,and the flow rate of the melt extruded from the spinneret will be more uniform.