Single Glass Fiber Drawing

In this process, molten glass is drawn through a nozzle by gravity and attenuated by tension from a winder to form fiberglass. Large free surface deformation and heat transfer are major factors in this process. The ratio of attenuated fiber cross-sectional area to initial cross-sectional area is defined as the draw ratio. The high draw-down ratio (1:10,000 and higher) makes it critical to understand the attenuation process as it influences fiber quality and productivity. Fluent software can be used to simulate advanced phenomena such as the wetting of the busher of fiber, the radius evolution as a function of external thermal effects, and the influence of the air surrounding the fibers.

A single glass fiber drawing was simulated by Dr. Bruno Purnode of Owens Corning using Fluent's polymer processing and glass forming CFD software POLYFLOW. POLYFLOW has unique free surface remeshing algorithms that allow it to handle large draw ratios and to calculate the fiber surface deformation while accounting for the highly non-linear viscosity relationship, surface tension, and special heat transfer laws. Dr. Purnode investigated several flow rates and process conditions of the drawing. The fiber diameter in the axial (draw) direction was compared with the experimental data in literature. The POLYFLOW results, at a draw ratio of 1:19,024, show excellent agreement with the experimental data.

POLYFLOW results, at a draw ratio of 1:19,024, show excellent agreement with the experimental data