Four types of flames join forces to make this eerie ‘blue whirl’
The ghostly blue flame stunned researchers when it first showed up unexpectedly in a laboratory experiment. Now scientists have determined the structure of this “blue whirl.” Four separate types of flames make up the blue whirl, researchers report August 12 in Science Advances. “It’s amazingly complex,” says engineer Elaine Oran of Texas A&M University in College Station. Reported in 2016, the blue whirl appeared when scientists ignited liquid fuel floating on water, within an enclosure designed so that air sweeping in created a vortex (SN: 8/18/16). A tornado of fire blazed before settling into a spinning blue flame several centimeters tall. The hue indicates that it burns without soot, suggesting that such flames could be useful in cleaning up oil spills or for more environmentally friendly power generation. Blue whirls can form in liquid fuel floating on water. The fire transitions from a raging tornado to a steady azure flame. Researchers have now...