Prelimiary Study On The Polymer Drawing Model Of The Air Centrifugal Spinning

Centrifugal spinning is a new method that makes submicron fibers from eithersolutions or melt polymers. This new method uses centrifugal force produced by rotatingspinnerets. In this thesis, an annular nozzle is installed around the spinneret hole and thepolymer will be attenuated further by both of the air force and centrifugal force. ALagrange type polymer drawing model of the air centrifugal spinning process is developedon the basis of numerical simulations of the air flow field. The polymer drawing model issolved numerically and the fiber trajectory and diameter are predicted. Preliminaryexperimental verfications are also performed.This thesis can divide into three parts:In Part one, the air flow field model is established and simulated numerically. The airvelocity distribution is obtained, which lays a foundation for the establishment of thepolymer drawing model of the air centrifugal spinning process.In Part two, the polymer drawing model of the centrifugal spinning process isestablished using Lagrange method. The polymer is assumed to be consisted of beards.Equations of the inertial centrifugal force, Coriolis inertial force, air force, viscoelasticforce and the surface tension force are deduced. And the kinematic equation and heattransfer equation are given. Computing methods and simulation procedures are describedin detail.In the last part, the polymer drawing model is solved numerically. The fiber trajectoryand diameter of the centrifugal spinning are computed. The fiber diameter produced by centrifugal spinning is compared to the measured fiber diameter and they have a fairlygood agreement. An air centrifugal spinning simluating equipmentt is built. The movingtrajectories of polyester filament in different conditions are captured by a high-speedphotography. The simulation results are consistent with the measured result, whichindicates the effectiveness of the model to a certain extent. Effects of the initial air velocityand polymer flow rate on the fiber trajectory and diameter are studied based on computersimulations. It is found that the fiber diameter is much smaller with the aid of air force thanwithout the air force. Both large initial air velocity and large mass flow rate can reduce thefiber diameter.To sum up, the Lagrange method is employed to establish the polymer drawing modelof the air centrifugal spinning based on numerical simulations of the air flow field. And themodel is verfied prelimiarily. This research provides a new method of producing finerfibers for the centrifugal spinning process.