Characterizing the cavitation development and acoustic spectrum in various liquids

Area of Science:

• Materials Science
• Fluid Dynamics
• Acoustics

Background:

• Cavitation is a complex phenomenon affecting various industrial processes.
• Understanding cavitation in molten metals is crucial but challenging due to high temperatures.
• Acoustic emission analysis offers a non-invasive method to study cavitation dynamics.

Purpose of the Study:

• To investigate cavitation behavior in transparent liquids and molten aluminum using a bespoke cavitometer.
• To correlate acoustic measurements with cavitation bubble dynamics.
• To identify a suitable liquid analogue for molten aluminum in cavitation studies.

Main Methods:

• Utilized a high-temperature cavitometer (up to 750°C) to measure acoustic spectra.
• Observed cavitation bubble structures and flow patterns in water, ethanol, and glycerine using digital videography.
• Employed a piezoelectric ultrasonic transducer at 20kHz and two power levels (50%, 100%).
• Measured acoustic emissions at varying distances from the ultrasonic source.

Main Results:

• Liquid behavior under sonication varied significantly based on physical properties.
• Non-dimensional analysis indicated water shares the closest cavitation characteristics with molten aluminum.
• Acoustic spectra of water and molten aluminum showed marked similarities.

Conclusions:

• Physical parameters of liquids critically influence cavitation regimes.
• Water serves as a viable physical analogue for molten aluminum in cavitation research.
• The developed cavitometer is effective for studying high-temperature cavitation phenomena.