CFD Modeling of Primary Breakup in an EIGA Atomizer for Titanium Alloy Powder Production

Area of Science:

• Materials Science
• Fluid Dynamics
• Additive Manufacturing

Background:

• Electrode induction melting gas atomization (EIGA) is crucial for producing spherical metal powders used in additive manufacturing.
• Understanding the primary atomization and fragmentation of liquid sheets is key to optimizing powder production.

Purpose of the Study:

• To describe the atomization and fragmentation of liquid sheets from a swirl nozzle during titanium alloy powder production.
• To simulate the primary disintegration of molten metal using computational fluid dynamics (CFD).

Main Methods:

• Employed a computational fluid dynamics (CFD) approach.
• Utilized the volume of fluid (VOF) method coupled with the large eddy simulation (LES) turbulence model.
• Simulated the primary breakup of molten metal in a swirl nozzle.

Main Results:

• High-speed spraying generates supersonic airflow within the atomization chamber.
• Recirculation zones are identified as the primary sites for atomization, enhancing turbulence and efficiency.
• The VOF-LES simulation successfully captured phenomena like conical melt-sheet formation, wave development, ligament formation, and perforation.
• Primary droplet sizes ranged from 200 to 800 μm.
• Increased gas pressure led to a decrease in atomized powder particle size and a narrower particle size distribution.

Conclusions:

• Recirculation zones are critical for efficient primary atomization in EIGA.
• The VOF-LES model provides a valuable tool for understanding and optimizing metal powder production processes.
• Gas pressure is a key parameter for controlling powder characteristics, enabling finer particles and narrower distributions.