Exploring the chemical and physical effects caused by acoustic bubbles in liquids with low dissolved gases

The goals of this project are:

• To measure/analyze the radical generation caused by bubbles in partially-degassed liquid.
• To measure/analyze the flow features (microstreaming) caused by bubbles in partially-degassed liquid.
• To test the feasibility of bubble microstreaming in liquid nitrogen in order to facilitate localised shear for cryo-biological applications.

The details

Ultrasound (sound with a frequency greater than 20 kHz) can help generate several bubbles from pre-existing dissolved gases in a liquid. But how do these bubbles behave when the amount of dissolved gases is substantially reduced? Our research aims to look into this aspect by evaluating the changes in liquid chemistry and physics due to the presence of bubble(s). These include several challenges and the identification of suitable control parameters, namely input power and frequency of the ultrasound.

The current project tests sonochemistry (chemistry due to sound waves and bubbles) and measures the streaming velocity (physical effect due to bubble oscillation in ultrasound) through in-house developed setups. The knowledge obtained is used to evaluate the stresses caused and is found to be prospective for bio-medical applications.

Graduate researcher profile: Joydip Mondal

What did you do before you started your PhD?

I did my Master of Technology in Cryogenic Engineering from IIT-Kharagpur.

What are the challenges of your research role?

The current work had several challenges that include capturing a temporally fast and spatially small entity i.e. bubble over a sustained duration. Understanding its dynamics required thorough numerical and experimental investigations to be in sync with one another.

What is the best part of your research role?

To be able to setup a testing facility that can cater to investigation of phenomenological effects triggered by common acoustic bubbles in target liquid.

Where do you wish to go after your PhD? Do you want to enter industry or continue doing more research?

I would like to pursue research and try to translate this knowledge from the lab to the society.

Supervision team

• The University of Melbourne: Professor Muthupandian Ashokkumar
• IIT Kharagpur: Professor Parthasarathi Ghosh and Doctor Rajaram Lakkaraju