A model for unsteady analysis of preform drawing

A model is introduced for analyzing diameter variations occurring in glass fibers drawn from preforms. The heat transfer is shown to be radiation-dominated, and approximate expressions for radiative exchange are developed. The expressions are used in the one-dimensional governing equations for extensional flows to derive a set of linearized disturbance equation as an eigenvalue problem. The sensitivity to an oscillatory take-up rate is also studied as a boundary-value problem. Calculated amplitudes of final diameter perturbations are found to agree well with experimental values.