Scientists at the University of Maryland’s A. James Clark School of Engineering have discovered a new kind of whirling flame that’s small, blue, and transparent, which offers a new way to achieve a clean burn as well as help in the clean-up of oil spills.
During a wildfire or urban fire, when hot air rises quickly from the ground, a fire whirl (also known as a fire tornado, firenado, or fire devil) occurs. While the overwhelming event can be extremely dangerous in nature, the University of Maryland researchers believe that the power of this new type of fire whirl can be used for good.
“A fire tornado has long been seen as this incredibly scary, destructive thing. But, like electricity, can you harness it for good? If we can understand it, then maybe we can control and use it,” said fire protection engineer, Michael Gollner, from the University of Maryland.
The authors explain in their paper how the blue whirl’s attractive color makes it notable. A yellow flame is a sign of very incomplete combustion and produces much particulates and air pollution.
“Blue whirls evolve from traditional yellow fire whirls. The yellow color is due to radiating soot particles, which form when there is not enough oxygen to burn the fuel completely,” paper co-author Elaine Oran said in a press statement.Blue in the whirl indicates there is enough oxygen for complete combustion, which means less or no soot, and is therefore a cleaner burn.” This cleaner burn could have noteworthy applications outside the lab.
“This is the first time fire whirls have been studied for their practical applications,” said Michael Gollner, co-author of the paper and assistant professor of fire protection engineering at the A. James Clark School of Engineering at the University of Maryland.
Initially, the researchers wanted to see how regular fire whirls behave on water. In the process, they discovered blue whirls, a previously unobserved type of fire tornado that burns more efficiently and more steadily while generating much lower emissions than their turbulent yellow counterparts.
This efficiency could see blue whirls being employed for cleaning up environmental disasters like oil spills, where cleanup efforts sometimes involve enclosing the crude oil into a thick layer that is then burned, producing clouds of toxic smoke. The ability of the blue whirls to burn the oil more completely would reduce the amount of pollutants that are released into the water and air. However, the team says that the main problem to that process is mounting the blue whirl from the small lab-made versions.
“Fire whirls are more efficient than other forms of combustion because they produce drastically increased heating to the surface of fuels, allowing them to burn faster and more completely,” says Gollner. “In our experiments over water, we’ve seen how the circulation fire whirls generate also helps to pull in fuels. If we can achieve a state akin to the blue whirl at larger scale, we can further reduce airborne emissions for a much cleaner means of spill cleanup.”
The findings of the research have been published in Proceedings of the National Academy of Sciences.