Computational optimization of a drafter for spunbonding polymeric filaments

This study presents a computational model to enhance the spunbonding drafter's performance. The existing design exhibits a significant risk of fiber breakage. To address this issue, an OpenFOAM computational fluid dynamics (CFD) solver is employed to simulate the airflow over the base geometry and its modified configurations following various design alterations. The collected data are analyzed for predefined optimization objectives: (a) maximize shear drag and thus draw on the filaments, (b) achieve maximum drawing uniformity, and (c) minimize the pressurized air consumption rate. These goals are set to produce more uniform filaments, reduce the breakage risk, and improve energy efficiency. We vary seven design parameters, ran many CFD simulations, and recommend a few enhancements for a drafter based on those. We identify a "braking effect" on the filaments and find that geometry significantly affects the internal airflow and, thus, the drawing process. Based on our findings, we propose widening the drafter, linearly diverging the walls at the lower section, linearly converging the walls at half of the upper section, and introducing an extensible length for drawing precision control.