The stability of 30µm diameter water-jet for jet guided laser machining

• Main Author: Du, Guannan
• Other Authors: Ng Yin Kwee
• Format: Theses and Dissertations
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/65150
• Institution: Nanyang Technological University

Combined water-jet process and laser machining, the water-jet guided laser processing is suitable in processing thin and sensitive material with a high degree of precision required Given that the stability of water-jet has direct effects on machining quality, a numeral model of J0,1.1m water-jet, considering the number of grids and the influence of meshes, has been built with GAMBIT in order to meet the requirements of micrometer order precision machining. Furthermore, the critical Reynolds number and the critical exit jet velocity of the case with J0,1.1m nozzle diameter have been found to make a comparison of turbulence flow and laminar flow with different exit jet velocities. Hence, the optimal exit jet velocity to get longest stable length of water-jet was found. A case of 15m/s is simulated in different degrees of vacuum, which suggests water-jets in vacuum are much more stable than those in atmospheric environment. Finally, a conjecture about water-jet simulation with smaller diameter of nozzle and the optimal chemical material of water-jet are proposed as future work. Keywords: Micro-water-jet guided laser; Stability of jet; CFD