An investigation of the formation of turbulent water and abrasive water jets

This study is concerned with the development of a knowledge base for the selection of nozzle geometry by investigating the mechanism of formation and behaviors of water and abrasive water jets. A numerical prediction of turbulent water flow inside various nozzles is developed. The analysis is based on the numerical solution of conservation equations of continuity and momentum as well as equations of turbulent kinetic energy and dissipation for 2-dimensional axisymmetric flow by using a finite element package, FIDAP.; The technique for determining velocities and forces of water jet and abrasive water jet with the Laser Transit Anemometer and Piezoelectric Force Transducer is validated by numerical prediction from the formulation indicated above. The velocity ratio of abrasive to water particle is about 0.45-0.65 which primarily depends on the alignment of the carbide tube and sapphire nozzle as well as on the mixing process.; The numerically predicted velocity at the nozzle exit complies generally well with the experimental data. The converging nozzles produce a concentrated high velocity jet which can be used for conventional cutting operations whereas the nozzles with diverging section produce cavities and circulation around jet which can be used for cleaning and polishing purposes. The conventional nozzle is diverging type and produces jets with a pulsing nature having particles accumulated and segregated cavities inside the jet as identified by high speed filming. The integration of experimental and numerical results provide a knowledge base for the nozzle design in various industrial applications.