Disturbance Propagation in the Melt Spinning Process

This work deals with the propagation of a disturbance acting on a fibre in the melt-spinning process, where molten polymer is ejected vertically downwards from an orifice before being drawn onto a wind-up spool. The disturbance may be produced by a sudden horizontal draught of air impinging on a part of the fibre. The flow is modeled as a wave propagating on a moving string under the influence of damping and variable tension. The amplitude of the disturbance is obtained in closed-form along the characteristics which emanate from the boundaries of the localised initial disturbance; the general solution of the damped disturbance is determined numerically. An important aspect of the model is the ability to predict the magnitude of this disturbance close to the orifice, where the extruded polymer is molten and therefore extremely sensitive to disturbances. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)