High Pressure Water Jet Nozzle Design And Structural Optimization

Water jet cutting nozzle as one of the key devices in the system, has an importantimpact on the dynamic performance and distribution of the jet flow field inside the nozzle.Good nozzle structure can improve the processing efficiency and accuracy. So it hasbecome a hot and difficult part for scholars to seek better structure by optimizing thenozzle parameters.In this thesis, designed five different nozzle streamlines of flow channel during to themain parameters and established physical model for each nozzle. Then discretized eachnozzle structure in the same way, established a solid-liquid two multiphase flow mode, atlast analyzed them with VOF methods. Finally it coupled the pressure and velocity insidethe nozzle jet by SIMPLE calculation method. After the simulation above, it can draw thatthe length of the transition section has a relatively large influence on the dynamicperformance and the flow field inside the nozzle. It can stabilize the jet and make thepressure as a cap-shaped distribution. The divergence angle of the nozzle has a relativelylarge influence on distribution of flow field at the outlet. The distribution of the jet is moremeticulous then no divergence angle. Fillet also has a obvious impact on the nozzle that thecore length of jet is longer than that without fillet. Therefore the nozzle with transitionsection, divergence angle and fillet has the best flow characteristics. That nozzle has largerradial velocity at the outlet, in favor of mixing jet and abrasive, so it is better to be themixed water jet cutting machine nozzle.Finally, this paper did a detailed simulation analysis through the aspect ratio of thenozzle, one of the main parameters, analyzing distribution of the flow field under adifferent aspect ratio In the context of the same diameter. Contrasting results, it reached aconclusion that in the same situation, the larger the aspect ratio, the better of the cluster atthe outlet, the larger of the dynamic pressure and axial speed，favorable for cutting. Byother major factors like the nozzle diameter of the nozzle, the transition section diameter,cone angle and divergence angle, optimized by orthogonal experiment method so that to obtain the optimum nozzle relative parameter combinations.