Optimal geometry design of double coat-hanger die for melt blowing process

Abstract

Design of the wide coat-hanger die is of significant importance for melt blowing system because the die plays a key role in the uniformity wider nonwoven webs. In this article, a mathematical method combining finite element and numerical simulation is used to optimize double coat-hanger die with uniform outlet velocity. A numerical approach is developed for design of double coat-hanger die with quadratic geometry manifold. The results indicate that melt flow direction in the manifold is along its lengthwise direction and the CV value of outlet velocity is decreased obviously. In addition, a 40:3 elliptic rate of ellipse cavity is inserted in the double coat-hanger die slot. It shows that the ellipse cavity and slot act together to improve flow distribution and pressure drop. The result of outlet velocity CV value is under 1 % for 3.4 meter width of double coat-hanger die. The current study provides a simple method to obtain wider coat-hanger die suitable for melt blowing commercial production.