Blue Whirl – a fire tornado burning soot-free

Researchers described a previously unobserved flame phenomenon: blue whirl. Blue whirls evolve from typical yellow fire whirls, but are smaller, very stable and completely blue, indicating soot-free burning. Credit: From fire whirls to blue whirls and combustion with reduced pollution Huahua Xiao, Michael J. Gollner, and Elaine S. Oran PNAS doi: