Optimizing Atomization Pressure Regimes for Battery Powder Synthesis
Maintaining gas atomization pressure between 2.5 MPa and 4.0 MPa optimizes particle sphericity while suppressing fine satellite dust in battery precursor synthesis.
Secondary Breakup Regime
Meaning
Aerodynamic force thresholds govern the further disintegration of primary liquid drops into smaller droplets within high-velocity gas streams. During melt atomization for metallic battery raw materials, the secondary breakup regime determines final powder size characteristics and distribution width. The physical regime classifies droplet fragmentation mechanisms based on relative Weber number and Ohnesorge number values.
Its applicability ends when aerodynamic drag forces drop below liquid surface tension forces or when droplets solidify.
Aerodynamic Shear
High relative velocity between expanding gas and liquid droplets creates intense drag forces that deform spherical drops into thin sheets or filaments. As flow conditions enter the secondary breakup regime, surface wave instabilities grow rapidly across the liquid droplet surface until shear stress shears away micro-droplets. Higher Weber numbers shift the dominant mechanism from bag breakup to shear stripping and catastrophic disintegration modes.
Droplet size shrinks by orders of magnitude within microseconds.
Droplet Instability
Surface tension acts as a restoring force, resisting external aerodynamic deformation until critical Weber number limits are surpassed. When operating inside the secondary breakup regime, viscous forces within high-viscosity molten alloys delay wave growth and increase required gas kinetic energy. Adjusting gas nozzle velocity alters local Weber numbers to favor rapid droplet fragmentation over slow bag deformation.
Viscous Boundary
Droplet fragmentation ceases immediately once heat transfer to the surrounding gas cools liquid droplets below solidus temperatures. Solidified particles passing through the secondary breakup regime retain their final dimensions regardless of subsequent gas velocity changes.