Meaning
Liquid breakup mechanisms are governed by the massive density difference between the metal stream and the high-velocity gas. This physical environment is characterized as high-density ratio multiphase flow in atomization nozzles. Managing this flow is difficult because the liquid metal is several thousand times denser than the driving gas.
The momentum transfer across the gas-liquid interface determines the size of the resulting droplets.
Flow Instability
Shear forces at the boundary of the molten metal stream create waves that grow until the stream ruptures. This initial disintegration is called primary breakup and occurs very close to the nozzle exit. High-density differences make these waves unstable and difficult to model or control.
Uncontrolled wave growth leads to wide variation in the final powder size.
Interface Tracking
Numerical simulations of these flows require specialized computational methods to track the sharp boundary between phases. Standard algorithms often struggle with mass conservation when density ratios exceed one thousand. Accurate modeling of this interface is essential for designing efficient nozzle geometries.
These calculations help engineers optimize the pressure of the inert gas without expensive physical trial-and-error.
Dispersion Behavior
Droplets formed during the breakup are swept away by the expanding gas jet. The heavy metal droplets have high inertia and do not follow the gas streamlines perfectly. This difference in trajectory creates a divergent spray cone.
