Discovering Fire

New Type of Flame Whirls in Engineering Lab

At one moment, Huahua Xiao and his colleagues were staring at a tornado of fire raging in a quartz glass enclosure. In the next, all that was left was a whirling blue top of flame—stable, elegantly proportioned and unlike anything that anyone in a lab full of fire experts had ever seen.

“When we saw it, we all became quiet,” says Xiao, an assistant research scientist in aerospace engineering. “Then we all said, ‘Oh my God.’”

Human evolution and history have been intertwined with fire—both its uses and dangers—but finding new forms of it isn’t an everyday occurrence. Yet the team of researchers including Xiao, Glenn L. Martin Engineering Professor Elaine Oran and Michael Gollner, assistant professor of fire protection engineering, appears to have done exactly that.

They introduced the flame in an August paper published online in Proceedings of the National Academy of Sciences, dubbing it the “blue whirl.”

Initially, they’d been studying fire whirls, tornado-like flames that can form during wildfires and greatly accelerate their spread. (The deadliest one in history towered over Tokyo in 1923 after an earthquake, killing tens of thousands.) Until recently, no one had considered the idea that they could be controlled and used for good.

“People have mainly studied fire whirls for fun, or out of curiosity,” says Gollner. But suspecting they could be harnessed to clean up oil spills, the researchers were creating small ones in the lab by igniting slicks of the flammable solvent heptane on a pool of water. When they inadvertently created the right fuel and ventilation conditions, the blue whirl appeared.

The color indicates it burns extremely cleanly and efficiently, Oran says, possibly making it a better tool to eradicate oil slicks than a regular fire whirl. (Although they didn’t present test results, the team confirmed crude oil can fuel the blue whirl.) It might also be perfect for other uses where low-emission combustion is needed, like clean energy generation.

But applications will come later. For now, the team is still working to explore the characteristics and dynamics of this new type of fire—for instance, how big it can grow, and how hot it can burn.

“It’s difficult not to speculate,” Oran says. “This is a phase no one’s seen before, and now we need to understand it.”