Putting bubbles on hold to unlock secrets of boiling
It can obviously be proven false if you're willing to wait around long enough, but researchers have added some truth to the old adage that a watched pot never boils. They've managed to put a boiling bubble on pause to learn more about the way such bubbles form when water boils.
Using a focused laser beam, Professor Shalabh Maroo's team at Syracuse University and collaborators at NIST and RPI, were essentially able to capture a single vapor bubble on a surface in a pool of liquid and keep it stable for hours rather than just milliseconds, as is the case in a pan of boiling water.
Aside from being a neat trick, pausing the bubble in place will help researchers better understand the fundamentals of the boiling process, which the team says is largely driven by the behavior of a very thin liquid film at the base of each vapor bubble. The bubbles, and this liquid film in particular, has previously been difficult to analyze due to the unpredictable and fleeting nature of the bubbles.
The team was able to pause and analyze vapor bubbles on both hydrophobic and hydrophilic surfaces using regular water that contains dissolved air, and also degassed water.
"The new understanding is going to help researchers design surface structures to achieve desired heat transfer, accurately predict as well as enhance boiling in outer space where lack of gravity causes bubbles to stay stationary on a heated surface, and create next-generation technology for thermal management in electronics."
The research has been published in its entirety in the journal Scientific Reports.
A "paused" bubble can be seen in the video below.
Source: Syracuse University