Characterization of stabilized water-beam fiber for water jet guided laser

In water jet guided laser processing technology, the stability of the water jet directly affects the processing quality. In order to investigate the flow characteristics of water jets, a numerical model of the flow field inside the water beam fiber is established, and the influence of different jet speeds and nozzle diameters on the formation of a stable water jet beam length with a flat cylindrical nozzle structure is analyzed. Computational fluid dynamics simulations show that a 120 μm diameter cylindrical nozzle structure with a length of 1 mm and no chamfered inlet has a maximum stabilized water jet length of 60 mm at a jet velocity of 70 m/s. The smaller the nozzle diameter, the more prone to water jet turbulence, and increasing the nozzle diameter can increase the stable length of the water jet to a certain extent. Finally, by conducting the water jet stable length experiment with different jet velocities, the maximum stable length of 65 mm is obtained and the accuracy of the simulation is verified, which provided a strong theoretical basis for the subsequent processing experiments.