Radial Temperature Differences During the Melt Spinning of Fibers

The production of glass and synthetic fibers by melt spinning is an important industrial process. Mathematical models of the process are needed to study the effects of rapid cooling and draw-down in the quench zone. In this investigation, a numerical model was developed to predict the temperature distribution in the fiber during melt spinning. This model uses the finite difference method to solve the governing differential equation for the problem. An estimate of the physical shape of the fiber was obtained by a fourth-order Runge-Kutta solution of a model presented in the literature (4 , 5) . This radius profile model compared favorably with experimental data reported by Harris (3) . The numerical model developed during this investigation was applied to a series of numerical experiments on glass fiber processing. These simulations used typical sets of operating conditions to see the effect of various operating parameters on the predicted radius profile , spin-line tension, and temperature distribution. The effects of spinneret capillary diameter, mass flow rate, ambient air temperature, spinning temperature, and elongational viscosity were investigated. For a typical set of operating conditions (Run Number 1) for the melt spinning of the glass studied, the predicted spinline tension was 3.28 x 10^-4 N, the solidification point was 0.03852 m, the radial temperature difference at the solidification point was 4.774 K, and the maximum radial temperature dif:erence was 10.231 K and occurred at an axial position of 0.00915 m. The results of the various runs showed that ambient air temperature and mass flow rate had a significant effect on the predicted radius profile, spinline tension , and temperature distribution. The spinning temperature was an important parameter, but its only significant effect was on the spinline tension. Spinneret capillary diameter and elongational viscosity had little effect on the predicted results