Numerical simulation of airflow behaviour and nozzle geometry on commingling for thermoplastic composites

The current study highlights the superiority of nozzles with forwarding airflow to produce the commingled yarns for thermoplastic composite applications. A new cost-effective nozzle that can produce good quality commingled yarns at low air pressure is introduced. 3D CFD simulation and experimental studies are conducted to investigate the effect of aerodynamics of three different cylindrical nozzle configurations (CONF) on the commingling process efficiency. Nozzle CONF I and II work on backwards airflow principles among these configures, while CONF III functions with forwarding airflow. Commingling process efficiency of nozzle designs is analysed in terms of vorticity magnitude, turbulence kinetic energy, turbulence intensity and radial velocity values obtained from the simulation study. Additionally, the structure of hybrid yarns is qualitatively analysed to support the simulation study. The study concludes that nozzle CONF I and III holds the excellent potential of mixing both reinforcement and matrix filaments across the yarn structure. In addition, these nozzles can form stable nips in the yarn structure and make the textile preforming effortless. Nozzle CONF III offers better yarn quality parameters over other nozzles at low processing pressure.

Automated summary

The study demonstrates the superiority of using nozzles with forwarding airflow to produce commingled yarns for thermoplastic composite applications. Nozzle configurations I and III exhibit better performance, mixing both reinforcement and matrix filaments effectively, and providing better yarn quality parameters at low processing pressure.