Study On Hydrodynamic Properties Of Melt Spinning Pack

Melt spinning is not only one of the main forming methods in the process of fiber production,but also an important process.As the core device of melt spinning process,the hydrodynamic properties of spinning packs can affect the quality of fiber products.However,the internal structure of the spinning pack is complex,which challenges the performance evaluation and structure optimization of the spinning pack.At the same time,the current research on the fluid flow characteristics of the spinning pack is lack.Therefore,this paper studies the flow and residence time distribution(RTD)characteristics of high viscosity fluid in spinning pack through experiments and numerical simulation,in order to provide guidance and reference for the optimization of hydrodynamic characteristics of spinning pack.In this paper,the flow field structure and RTD characteristics of the fluid in the spinning pack are studied experimentally.The main research methods include particle image velocimetry(PIV)and digital image processing(DIP).The experimental results are compared with the numerical simulation results to verify the accuracy and reliability of the species transport model.Then,the effects of porous media,pressure plate,guide plate,spinneret structure and operating conditions on the fluid flow in the spinning pack were studied by using the validated model.Finally,based on the experimental and numerical simulation results,a mathematical model was established to describe the fluid RTD in the spinning pack.The results show that the porous media and pressure plate can effectively reduce the flow dead zone and facilitate the uniform distribution of the fluid in the spinning pack.The guide plate plays a role of gathering and redistributing the fluid in the spinning module,but it makes more fluid with longer residence time appear in the module.Smaller diameter of spinneret hole is more conducive to the uniform distribution of outlet flow,but has no significant effect on RTD.The mean residence time(MRT)of the fluid in the spinning pack is inversely proportional to the inlet velocity.A one-dimensional axial dispersion model is established for the fluid in the spinning pack,which can better describe the residence time distribution characteristics of the fluid.