Meaning
Spatial arrangement of compression and expansion waves created by supersonic gas jets emerging from atomization nozzles. The shock wave pattern dictates the local pressure distribution and gas velocity in the region where the liquid metal is introduced. This aerodynamic configuration is a function of the gas supply pressure and the design of the nozzle.
Wave Structure
Gas expanding from the nozzle exit forms a series of alternating expansion fans and compression waves known as shock diamonds. These features create a repetitive pattern of high-pressure and low-pressure regions along the jet axis. The strength of these waves decreases as the gas travels further from the nozzle exit and mixes with the ambient atmosphere.
This structured flow field determines where the gas possesses the highest kinetic energy.
Gas Metal Interface
Positioning the liquid delivery tube relative to these waves is critical for maintaining stable flow conditions. If a compression shock wave sits too close to the melt tip, the local high pressure can force liquid metal backward or cause nozzle clogging. Alternatively, positioning the melt tip in a region of expansion fans generates a favorable suction pressure that pulls the liquid metal into the atomization zone.
Operators must optimize the gas pressure to align these waves safely.
Performance Impact
Correctly managed supersonic wave arrays maximize the kinetic energy transferred from the gas to the liquid metal. This high energy transfer enhances the primary and secondary breakup of the liquid, which results in a higher yield of fine powder. Properly aligned wave structures also minimize the consumption of expensive inert gas per kilogram of metal powder produced.
