Cavitation clusters in lipid systems - surface effects, local heating and streamer formation

Area of Science:

• Fluid Dynamics
• Acoustics
• Materials Science

Background:

• Cavitation phenomena are critical in various industrial processes, including food processing.
• Understanding cavitation in lipid-based materials like sunflower oil is essential for optimizing these processes.
• Previous research has primarily focused on cavitation in water, with limited data on lipid systems.

Purpose of the Study:

• To characterize cavitation clusters and streamers in sunflower oil.
• To compare cavitation behavior in lipid systems with that in water.
• To investigate the factors influencing streamer formation and dynamics in oils.

Main Methods:

• High-speed camera imaging to visualize cavitation structures.
• Laser scattering and pressure measurements to analyze cavitation dynamics.
• Dual thermocouple measurements to detect local heating effects.
• Characterization of lipid systems using a piston-like emitter (PLE).

Main Results:

• Cavitation clusters in aged sunflower oil exhibit varied collapse periodicity related to drive amplitude.
• A distinct, collimated streamer is observed in lipid media, differing from the less distinct water cavitation plume.
• Bubble velocities within the lipid streamer reach approximately 10 m/s.
• Local heating effects are detected within the lipid streamers.

Conclusions:

• Lipid systems display unique cavitation streamer characteristics compared to water.
• Viscosity, temperature, and outgassing are identified as key factors in lipid streamer formation.
• The findings provide valuable insights into cavitation dynamics relevant to food processing.