Multibubble sonoluminescence in supercooled water.

Area of Science:

• Acoustics
• Physical Chemistry
• Materials Science

Background:

• Supercooled water is prone to ice crystallization.
• Cavitation can be induced by ultrasound.
• Sonoluminescence (SL) is light emission from collapsing bubbles.

Purpose of the Study:

• To investigate cavitation and crystallization in supercooled water using ultrasound.
• To assess sonoluminescence from cavitation bubbles in supercooled water.
• To determine the effect of supercooling on SL intensity and bubble collapse temperature.

Main Methods:

• Inducing cavitation in supercooled water with 20 kHz ultrasound pulses.
• Imaging cavitation and crystallization events with a high-speed camera.
• Measuring sonoluminescence using an image intensifier and summing light emission events.

Main Results:

• Short ultrasound pulses reduce the probability of ice crystallization in supercooled water.
• Sonoluminescence was observed from cavitation bubbles in supercooled water.
• SL intensity increased with decreasing temperature (increasing supercooling).
• Calculations indicated increased bubble collapse peak temperature with supercooling, with a predicted fall-off at higher supercooling levels.

Conclusions:

• Controlled ultrasound pulses can stabilize supercooled water against crystallization.
• Sonoluminescence provides insights into bubble dynamics and thermodynamics in supercooled liquids.
• The observed SL behavior is consistent with reduced vapor pressure and increased bubble collapse temperatures at higher supercooling.