More than a decade has passed since Michael Gollner and his colleagues first watched a viral YouTube video of a fire tornado fueled by Jim Beam bourbon.
A warehouse in Kentucky had just been struck by lightning, spilling about 1 million gallons of flammable spirits into a nearby reservoir. But as the flames raced across the water, something in the stars in the atmosphere aligned. The flames coalesced into a towering vortex of fire, commonly known as a fire tornado.
“We looked at it and thought, ‘Wow, this could be successfully applied to oil spill treatment,'” said Gollner, a professor of mechanical engineering at the University of California, Berkeley Fire Research Institute. “I wonder if you could do that on purpose?”
The French fireworks show Manda Lights intentionally created this tornado of fire. Credit: Ima Julien Cie Manda Lights/Wikimedia Commons, CC BY-SA 4.0
In fact, it was possible. As Gollner and his colleagues recently reported, fuelFire Whirlwind offers the potential to clean up oil spills faster and cleaner than existing methods.
Oil spill response depends on quick and immediate action. After just 24 hours, the crude oil naturally absorbs water and begins to sink beneath the waves, wreaking havoc on marine life.
Along with other key techniques such as containment and recovery and chemical dispersal, in-situ burning through ‘fire pools’ has been adopted as an imperfect but inevitable means of dealing with oil spills. The fire pool stops the oil spill from spreading, but it also sends clouds of smoke into the atmosphere and leaves a layer of tar that sinks to the ocean floor.
The European Space Agency’s Envisat satellite captured images of the Deepwater Horizon oil spill a week after the accident. Credit: European Space Agency, CC BY-SA 3.0 IGO
fire away
If it’s far from the coast, there’s basically no other option than to corral it and burn it. ”
Gollner said environmental agencies such as the Bureau of Safety and Environmental Enforcement (BSEE) were “very excited about the concept of changing what has been the standard for cleanup since Exxon Valdez.” “There’s a lot of knowledge out there, and there are conferences every year about oil spills. … But if you’re far from the coast, you basically have little choice but to corral it and burn it.”
In May 2023, Gollner, Texas A&M aerospace engineering professor Elaine Oran, and 20 others gathered at the Texas A&M Engineering Extension Service (TEEX) Brayton Fire Training Range in collaboration with BSEE. The researchers constructed three 5-metre-high walls to direct airflow over a central pool of water about 3 meters square and 1.2 meters deep, and then placed a 15- or 40-millimetre layer of oil on top. The scale of the apparatus was significantly different from traditional fire swirl experiments, which are primarily conducted in laboratories.
“Everything is bigger in Texas,” Gollner said.
Three walls built with well-placed gaps allow the air sucked in by the flames to swirl, forming a combustion tower. The intense whirlwind effectively acted as a vortex furnace, increasing the combustion rate by 40% compared to traditional fire pools while vaporizing many of the particles that pollute the air. Emissions of PM2.5, particles less than 2.5 micrometers in diameter that can be harmful to human health, were 40% lower in the fire vortex experiment than in the pool fire.
The team created these fire tornadoes in a custom-built, triple-walled room at the TEEX Brayton Fire Training Range. Credit: Wuquan Cui/Michael Gollner
The cameras that were recording the fire vortex did their best to survive the experiment. Credit: Wuquan Cui/Michael Gollner
Why this reduction in soot occurs is still largely a mystery. To explore this question, Gollner explained, new experimental equipment needs to be built to take measurements from within the flame itself. On the other hand, in field experiments, one of the fire whirls succeeded in consuming 95% of the available fuel, while the remaining tests were prematurely extinguished, reducing the overall rate. The surrounding wind conditions on the day of the experiment may also have had some influence.
Creating a firestorm in the suburbs of College Station, Texas, even under semi-ideal conditions, remains a much easier task than creating a firestorm in the middle of a disaster. Towing a triple-walled tornado generator out into the open sea is as much a matter of marine and naval engineering as it is fire science. In an experiment at TEEX, a captured finnard was elevated the entire length of a 5-meter wall. While lower walls may make it easier to transport floating rigs, the resulting mixing of oxygen and fuel may actually make subsequent air pollution worse rather than better.
Years ago, Michael Gollner was attending a fire safety conference when he received a frantic phone call. A test in Maryland caused a boilover that sprayed walls and set part of the test equipment on fire. Gollner has kept the charred remains ever since, with a photo of it on his computer labeled “Don’t set research on fire.” Credit: Michael Gollner
Ali Rangwala, a professor of fire protection engineering at Worcester Polytechnic Institute (WPI) who is not involved in the project, also encourages scientific due diligence. Fire whirlwinds “work very well if the boundary conditions are fixed and well designed,” he said in an email. iosadded that these vortices have not yet been tested in open ocean with waves, and the required infrastructure could be expensive. (Rangwala helped conduct the fire swirl experiment with Gorner at WPI, but maintains no relationship with the project.)
“The honest truth is this is a disaster scene,” Gollner said. The Deepwater Horizon spill, one of the largest oil spills in history, spilled more than 750 million liters (200 million gallons) into the Gulf of Mexico. That was in 2010. “We haven’t seen a major oil spill in a long time, and interest in it has wavered. … We need a more multidisciplinary team and more testing. Is anyone willing to do it? Unfortunately, I think we’ll see another one over time.”
pave the way
Mr. Gollner emphasized the important value of basic research, a body of research that is driven not only by application but also by fascination. What began as a simple appreciation of nature’s wonders has the potential to transform the field in ways researchers have yet to imagine.
“Fire is beautiful whether it’s swirling or not,” Gollner says. “It’s a natural flow tracer. You see fluid mechanics and combustion interacting. … It’s all the physics coming together. It’s really beautiful.”
—Jonathan Feakins, science writer
