Study On The Air Flow Field And Polymer Threadline Motion Model Of The Air Centrifugal Spinning

The centrifugal spinning is a method that polymer solution or melt is extruded from the high-speed rotating spinneret orifice and drawn into micro-nano fibers under centrifugal force. This method is a breakthrough in producing nanofibers for its wide range of raw materials and mass production. To make further effort to achieve reduction of fiber diameter, air centrifugal spinning is put forward by combining centrifugal spinning and melt-blown technology. By this means, both the air force and centrifugal force act on the polymer threadline in the drawing process. In this work, numerical simulations and experimental measurements of air flow field are described in detail. Polymer threadline motion model of the air centrifugal spinning is also established and solved.This thesis consists of five chaptersChapter one gives the literature review. This chapter presents the research findings given by domestic and foreign researchers in the relevant fields, which are the technology of centrifugal spinning, numerical simulations and experimental researches of air flow field and the models of polymer drawing.Chapter two provides a description of the numerical simulations of air centrifugal spinning, including the establishment and solution of the air flow field. In this chapter, two sorts of software are employed. The gambit software is used to build a geometric model of the circular nozzles, obtain the meshes of computational domains and specify the boundaries of computational domains. And the Fluent software is utilized to determine the governing equations and the turbulence model, set the boundary conditions and the initial conditions, obtain the converged solution of the air flow field. This chapter also presents numerical simulation results of eight kinds of air flow fields. The distributions of air velocity are got and analyzed.In Chapter three, focus is given on the experimental measurements of air flow fields around rotating spinnerets. IFA300 hot wire anemometer is used to get the distributions of air velocity. Numerical simulation results are compared with these measurements. It is shown that there is a same trend between these two results, which proves that numerical simulations of air flow field is valid.Chapter four describes the establishment and solution of polymer threadline motion model of air centrifugal spinning. On the basis of forces analysis of polymer threadline, this motion model is established by Lagrange approach and solved by RKF algorithm. Several parameters are studied to determine the impacts that they have on the polymer threadline motion trajectory. These parameters include the initial air velocity, flow rate and the rotational speed of spinneret.In Chapter five, the achievements and deficiencies of research as well as further work are presented.