Posting in Government
The Defense Advanced Research Projects Agency (DARPA) has taken a novel approach to combating fire - developing a bass cannon that can put out fires with pure sound.
The Defense Advanced Research Projects Agency (DARPA) has taken a novel approach to combating fire -- developing a bass cannon that can put out fires with pure sound.
A new video from the agency shows how to extinguish burning fuel by trapping it in an acoustic field generated by surrounding speakers. Officially referred to as "acoustic suppression of flame", each speaker emits a low frequency to increase the rate of air velocity. By manipulating this, the origin of the fire's combustion -- the flame boundary layer -- can be disrupted.
When the air velocity changes, the flame boundary layer -- where combustion occurs -- begins to thin. Not only this, but by disturbing the surface, the acoustic fields lead to higher fuel vaporizaton. This results in widening the flame, but more importantly, it brings down the overall temperature of a blaze.
In the video below, the demonstrators have shown that by using the correct bass frequencies, a flame can be extinguished quickly and effectively.
Remarking on the overall impact of the research, DARPA program manager 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."
Traditionally, fire-suppression technologies focus on disrupting the chemical reactions that result in combustion. However, if you take a physics perspective on the make-up of flames, the phenomenon is cold plasma. DARPA theorized that by using techniques applied in physics rather than chemistry, it may be possible to extinguish flames without water or solution.
This kind of technology, once developed further, could be applied to enclosed spaces -- such as military ship holds, ground vehicles or aircraft cockpits. Blazes in these kinds of areas can cause extreme damage, and traditional methods to combat fire may not be easy to carry out. An example is the shipboard fire on the aircraft carrier USS George Washington in May 2008 which burned for 12 hours, causing an estimated $70 million in damage.
Image credit: DARPA
Jul 16, 2012
Boys and girls, don't be so quick to criticize this discovery/re-discovery. I would suggest that it's easier and far more sanitary to carry around an electric powered fire extinguisher than a Bass or Carp shooting cannon for extinguishing a fire. What I want to know is whether or not the same principles of physics used to disrupt combustion can be used to enhance combustion. If I play heavy metal music under the hood really loud, will I get better mileage?
Along with the 747 Laser Beam Jets developed to shoot down Missles, (etc.) Already in the arsenal,, add a Bass Cannon 747 or other "Skunk Works" Delivery Vehicles for "Various" Uses . ( For those who will make fun of this, no worries, this comment has been "Captured" and Read by those who need to see it ).
firing a cannon loaded with bass at a fire might very well put it out, but so would the same load of carp (being very careful with the spelling of that).
Back in the day they used to use dynamite to put out oil fires.The force of the explosion disrupted the fire and it consumed most of the oxygen. If you could design something the size of a flame thrower that actually disrupted the flames in close proximity, it might be of use because you could then use an extension cord instead of a fire hose. That said, if the sound wave ended up destroying what you are trying to save then its not necessarily a good alternative.
Sorry, I have nothing but visions of the authorities deploying Motorhead v's Forest Fire in my head. Ace of Spades indeed - LOL.
In the demo, the flame source is about half the size of the acoustic tube which appears on 2 opposing sides of the flame source. A small hand held fire extinguisher would be easier to put out this flame and I can't see from this demo how you would surround a building or shipboard fire with such a cumbersome apparatus.
If the sound has to be loud enough to cause ear damage or to cause collateral damage to items within close range of the fire, this may not be a good idea. In our main server room, we have a gas extinguisher system that simply pushes all the oxygen out of the room. It's non-toxic and if a person is caught in the blast, they only have to hold their breath as they walk out. More details about amplitude and frequency of the acoustic extinguisher would be welcome.