Novel Design in Venturi-Type Nozzle by Selective Laser Melting for Enhancement in Microbubble Generation

Area of Science:

• Materials Science and Engineering
• Fluid Dynamics
• Chemical Engineering

Background:

• Conventional methods struggle to fabricate microscale structures for enhanced gas-liquid interaction.
• Venturi-type nozzles are crucial in microbubble generation for various applications.
• Optimizing nozzle design is key to improving microbubble production efficiency.

Purpose of the Study:

• To fabricate microscale stainless steel 316L structures using selective laser melting (SLM) on Venturi-type nozzles.
• To investigate the effect of these SLM structures on microbubble generation efficiency.
• To determine optimal SLM parameters for high-density, austenite-phase SS316L fabrication.

Main Methods:

• Selective laser melting (SLM) was used to fabricate SS316L structures on Venturi nozzle distribution plates.
• Optimization of SLM parameters including laser power, scan speed, layer thickness, and hatch distance.
• Microbubble generation tests were conducted at varying dissolution tank pressures (0.20–0.30 MPa) comparing SLM-assisted and plain nozzles.

Main Results:

• Optimal SLM parameters (140 W laser power, 100 mm/s scan speed, 30 µm layer thickness, 120 µm hatch distance) yielded high relative density and maintained the austenite phase.
• SLM-assisted nozzles produced smaller average microbubble sizes (31.8 µm) compared to plain nozzles (38.8 µm).
• At 0.30 MPa, the SLM-assisted nozzle generated a 102.1% increase in microbubbles (52,368) versus the plain nozzle (25,907).

Conclusions:

• SLM is an effective method for fabricating microstructures that enhance microbubble generation in Venturi nozzles.
• The optimized SLM structures significantly improve both the quantity and quality (size) of generated microbubbles.
• This technology holds promise for applications in water treatment, biomedical processes, and chemical engineering.