Air Recirculation and Its Effect on Microfiber Spinning in Blunt-Die Melt Blowing

In the present work, approaches of the Computational Fluid Dynamics (CFD) simulation, the Particle Image Velocimetry (PIV) measurement, and the spinning experiment were applied to investigate the phenomenon of air recirculation in blunt-die melt-blown airflow. Firstly, the characteristics of air recirculation were explored by CFD simulation. The simulation results predicted that the air recirculation generated a lateral air velocity along the nose-piece direction. Then, the air circulation was experimental verified by using PIV technique. The PIV results confirmed the predicted conclusions of CFD simulation. Finally, the effect of air recirculation on the microfiber spinning during the melt-blown process was experimentally investigated by a spinning experiment using a blunt die with nose-piece width of 2.56 mm. The spinning results indicated that the air circulation had a tendency of splitting the normal polymeric stream, which played negative effect on the continuity of microfiber spinning. This work is expected to provide some clues to melt-blown die design and the quality control of nonwoven products.