Numerical model of an air-jet loom main nozzle for drag forces evaluation

The flow field inside an air-jet loom main nozzle is studied numerically, by means of a two-dimensional model implemented in the commercial computational fluid dynamics (CFD) code Fluent. In order to determine which physical model could allow a better prediction of the nozzle behavior, preliminary simulations were carried out on a basic geometry configuration, changing flow models and comparing results with available experimental data. Having done the model setup, simulations aimed at evaluating drag force on the weft yarn were performed on various geometry configurations; in particular, the influence of acceleration tube length, shape and size on drag force was evaluated. Results gave some guidelines for future prototyping and experimentation.