Numerical analysis of airflow fields in new modified melt-blowing dies

Abstract

Considerable research has been devoted to the optimization of die configuration to effectively reduce both fiber diameter and roping defects. While some progress has been made, the challenge of developing an improvement method for the melt-blowing die that maintains the production efficiency of the original equipment while not damaging it and without introducing unnecessary energy consumption, still persists. Herein, we report a series of new modified dies featuring gradually shrinking air slots along with an internal flow stabilizer or arc nose piece that can be obtained without damaging the original die. The simulation results indicate that the new modified die demonstrated a remarkable enhancement in various aspects. Notably, it resulted in a substantial increase of 40.61% and 11.18 K in average centerline air velocity and average air stagnation temperature, respectively, while simultaneously achieving a remarkable reduction of 49.45% in average centerline turbulence kinetic energy. In addition, our modifications yielded an impressive maximum reduction of 23.08% in fiber diameter. The simulated motion characteristics of the polymer jet demonstrated that the new modified die exhibited superior polymer jet attenuation and lower whipping amplitude. The findings of this study indicate that the new modified die, which incorporates gradually shrinking air slots along with an internal flow stabilizer or arc nose piece, shows promise for the production of melt-blown nonwovens with smaller fiber sizes and a reduced occurrence of roping defects. Future research and development will concentrate on practically implementing this technology in melt-blowing production.