Understanding the breakup behaviors of liquid jet in gas atomization for powder production

[Display omitted] •A new in-situ gas atomization simulation system is built and the behaviors of liquids are successfully observed.•The primary breakup mode is firstly divided into four modes. The secondary breakup behavior in gas atomization is first observed, and four secondary breakup modes are clarified based on the experimental results.•We put forward an optimal method for atomizer by adopting the reasonable combination of two breakup modes, where membranous breakup is adopted as primary breakup mode and catastrophic breakup is adopted as secondary breakup mode. Gas atomization (GA) is the main method to produce metal powders for additive manufacturing (AM) because of its low cost and high efficiency. However, the liquid breakup behaviors in high-speed gas flow during GA remains unclear, especially the primary breakup in the near field and the secondary breakup in the far field. Great difficulty exists in in-situ observation of the interactions between high-speed gas and high-temperature molten metal because of the limitations of the enclosed environment. Here, we built a new GA simulation system with a close-coupled atomizer utilizing liquids with low melting temperature, such as water, glycerin, etc. We use a high-speed camera to capture the evolution of liquid behaviors at various parameters. We first reveal that four primary breakup modes and four secondary breakup modes exist in the GA process, and these breakup modes significantly influence the particle size distribution (PSD) and the defects of the powder. Besides, the breakup modes are clarified by the dimensionless analysis. This manuscript provides an effective experimental platform to understand the breakup behaviors of the liquid jet in GA and suggests the optimal breakup mode for powder production.