Dynamic modeling and simulation of bottom outlet air flow field in wide slot positive pressure spunbonding drawing process

摘要

The air jet flow has an important influence in wide slot positive pressure spunbonding process that not only includes the filament fiber diameter, crystallinity, and birefringence, but also the fiber web evenness. In this work, the air drawing model and the air jet flow field model of bottom outlet in spunbonding process are established and studied. The characteristics and regularities of the plane air jet flow in wide slot positive pressure spunbonding process are also demonstrated. It is simulated by means of the finite difference method. The numerical simulation computation results of distribution of the air velocity match quite well with the experimental data. The air drawing model of polymer is solved with the help of the distribution of the air velocity. The predicted filament fiber diameter, crystallinity, and birefringence agree well with the experimental data. It was found that higher initial velocity and initial temperature of air can yield finer fibers, and its effect was very significant. The results also reveal the great potential for this research in the computer-assisted design of spunbonding technology and equipment.