A recently discovered soot-free flame called a blue vortex – which consumes all the fuel it encounters – actually consists of three different flame structures swirling together in one other world flower ring, according to the first study to identify how these forming unique flames. By opening up the structure of the blue vortex, the findings could inform potential applications of the flame for efficient combustion with low emissions.
“Only when we understand the structure can we tame it, scale it, and create it for fun,” write Joseph Chung and colleagues in the study.
Scientists recently discovered the formation of a blue vortex when experimenting with fire vortices produced by burning liquid hydrocarbon fuels on a water base. But although further research has since produced temperature maps of blue swirls and informed how they can be stabilized, their flame structure and dynamics – especially how they form from a fire vortex – have remained mystical.
To simulate how blue whirls arise, Chung et al. coupled 3D, time-dependent equation describing the motion of viscous liquids to a model for fuel conversion and release of chemical energy. The researchers began by simulating experimental conditions, and then adjusting physical parameters such as fuel and air size and velocity in their calculations until a blue vortex materialized.
The researchers found that the ethereal flame consists of three different flames: a diffusion flame, in which the fuel and the oxidizer are separated before burning, and premix rich (with too much fuel) and lean (with too much air) flames. Chung et al. conclude that their research provides a tool to further explore this phenomenon, including if the flame can be made directly and safely scaled up to larger sizes.
Reference: August 12, 2020, Science Advances.
DOI: 10.1126 / sciadv.aba0827
