A Two-Dimensional Analysis of a Heated Free Jet at Low Reynolds Numbers

Abstract

To spin polymers and glass into continuous fibers, hot molten material is made to flow through a nozzle into air, thus forming a free liquid jet. This cools as it proceeds through the air and the solid fiber is collected on a rotating drum. This maintains a tension on the jet causing it to attenuate as it cools. An approximate integral technique is presented to investigate the relative importance of two-dimensional fluid mechanics for a variable viscosity glass jet in the region of the jet within four to five nozzle diameters of the nozzle exit. The results, when compared with those of an existing analysis based on one-dimensional velocity and temperature profiles, indicate that two-dimensional fluid dynamic effects exert very little influence on the jet shape while small changes in the temperature distribution cause significant changes in the jet behavior. A limited number of experiments performed with a chlorinated polymer provided a very simple and inexpensive means of modeling glass flow and also served to verify the results of the existing analysis over a different range of property values as compared to glass.