Ever since one guy decided to set an arrow alight and shoot it at another, fire has presented a real and present danger for any and all militaries. Anything from troop transports to nuclear submarines are susceptible to going up in smoke, and can prove both extremely hazardous and expensive.
However, the regular technique of putting it out with water might not only be impractical, but may prove impossible dependant on what is burning. DARPA decided to attempt putting it out with another force – sound.
Home to the US military’s cutting edge technology research teams, many a seemingly insane research project, and featured in some way with every conspiracy theory you can mention since its inception, DARPA has had a history of suggesting the bizarre, and then backing it up.
In this instance, preliminary tests have been a success. However, the team have admitted that they haven’t quite figured out how the technology would be applied on the battlefield.
The Instant Fire Suppression (IFS) programme was launched by DARPA back in 2008 following demands from the US Military to look into effective and innovative ways of firefighting.
Last year, IFS moved from planning to testing.
"From a physics perspective, flames are cold plasmas. Darpa theorised that by using physics techniques rather than combustion chemistry, it might be possible to manipulate and extinguish flames," said DARPA in a web-release.
Electromagnetics had also been selected to see if they could be employed to fight fire alongside manipulating sound. A hand-held electrode was explored as a method of suppressing small methane and liquid field fires.
Utilising the power of acoustics, the team of researchers also used speakers in another experiment to pump out specific frequencies that may extinguish fire.
"The acoustic field increases the air velocity. As the velocity goes up, the flame boundary layer, where combustion occurs, thins, making it easier to disrupt the flame," DARPA explained.
Unfortunately, despite both methods proving successful, it remains unclear how the discoveries can be incorporated. Naturally, it wouldn’t be very cost effective to line every wall of a tank or battleship with a range of Marshall Amps.
DARPA’s Matthew Goodman said, "We have shown that the physics of combustion still has surprises in store for us. Perhaps these results will spur new ideas and applications in combustion research."