Investigation on magnetic and flow field in magnetorheological jet machining

The instability and spreading out of jet flow outside the focusing tube involved in abrasive waterjet machining can be prevented by using magnetorheological (MR) fluid. The collimated and coherent MR jet in the presence of external axial magnetic field is potential to give a preferable erosion footprint and processing performance. In this research, a magnetic generator was developed and installed on an abrasive waterjet machining system to conduct MR jet erosion experiments on alumina. The induced magnetic field and jet flow field were numerically analyzed to evaluate their effects on material removal. The results indicated that the magnetic flux density increases with an increment of excitation current. The concentration of jet flow can be significantly enhanced by applying external magnetic field, and the velocity attenuation along the flowing direction due to the jet diffusion is restrained. The experimental results indicated that the range of crater is relatively smaller, and the erosion depth is larger when applying magnetic field, which can verify the validity of simulation results.

Automated summary

The use of magnetorheological (MR) fluid can prevent the instability and spreading out of jet flow outside the focusing tube in abrasive waterjet machining, while an external axial magnetic field can improve erosion footprint and processing performance. Results from experiments on alumina validate the effectiveness of applying magnetic field to enhance jet flow concentration and restrain velocity attenuation.