Analysis of the Temperature Field from Multiple Jets in the Schwarz Melt Blowing Die Using Computational Fluid Dynamics

Melt blowing dies are used to manufacture fine polymer fibers rapidly. The Schwarz die is a type of melt blowing die that uses multiple jets to produce numerous polymer fibers simultaneously. Heated air flows through the air jets, each of which encloses a polymer capillary. The experimentally measured velocity and temperature fields from a Schwarz die can be reproduced using the k-(epsilon) turbulence model. Six different multihole die geometries were simulated in three dimensions with this model. The geometries differed only in the spacing between the jets. The temperature field from the array showed significant variations from the temperature field from a single annular jet. The temperature field from the multihole dies decayed more slowly than that from a single annular jet. In addition, the temperature field from the different multihole geometries showed variations from each other, leading to observations relating to the interactions between multiple jets. As the spacing between the jets increased, the distance required for the temperature fields from neighboring jets to converge also increased.