A few years ago, while investigating more efficient ways of using fire to clean up oil spills in the ocean, researchers discovered an elusive phenomenon called the 'blue whirl flame' " a soot-free flame that consumes all the fuel it encounters. Recently, researchers, while experimenting with fire whirls, accidentally generated this clean flame.
According to a report in Science News, the phenomenon was first reported in 2016 when researchers ignited liquid fuel floating on water within an enclosed apparatus so that the air sweeping in created a vortex. Subsequently, a tornado of fire blazed before settling into a spinning blue flame that was a few centimetres tall. The colours was an indication that the fire burnt without any soot, suggesting that such flames could be useful in cleaning up oil spills for more environmentally friendly power generation.
As per a New Scientist report, Joseph Chung and Xiao Zhang from the University of Maryland and their colleagues have now created a computer simulation of the experimental conditions that generated the original blue whirl flame.
Researchers found that the blue whirl is actually the result of three different types of flames merging into one, including the outer flame where there is more oxygen than fuel, and two inner flames where the ration of fuel to oxygen is higher.
As per the report, Chung said that knowing the constituent flame type that make up the blue whirl's structure could help create it in more controlled conditions without going through the fire whirl stage.
Zhang said, "The blue whirl itself shows a possible way of burning that could greatly reduce this pollution and so we are very motivated to explore this potential for cleaner combustion."
Zhang added that soot production in the blue whirl is much lower than regular yellow flame and there is interest in exploring the possibility to mimic the combustion process of the blue whirl to reduce emissions.
The results of the study were published in the journal Science Advances.