Posted on 03/29/2011 9:13:07 AM PDT by thackney
Since the time humans first began to control fire around 400,000 years ago we have had just a few simple tools to douse the flames.
Now some Harvard University chemists believe they have found a way to bring fire suppression into the digital age by controlling flames with electricity.
During a series of experiments to study the chemical nature of fire, scientists were surprised to learn that by applying an electrical field to a burning flame it easily went out. All they needed to do is wave a wand-like, electrified metal wire near the flame.
‘What did I do wrong?’
“As a scientist you find it fascinating, but you have to control your emotions and ask how nature is trying to deceive you,” Ludovico Cademartiri recalled about the experiment. “I was thinking, ‘What is wrong with this experiment? What did I do wrong’”
As it turns out, he and other chemists in the lab of Harvard chemist George Whitesides had done nothing wrong.
Nearly all previous study of flames and electric fields involved those generated by direct current, or DC, instead of alternating current.
“What we discovered is that by applying an oscillation field, AC voltage, the effects are completely different,” Cademartiri said. He reported the findings Sunday at the national meeting of the American Chemical Society.
In their experiments the researchers used a 600-watt power source — about the same as a modest home-theater stereo — to create an electric field near flames as large as 18 inches tall.
They found the field created an organized “flow” of charged particles inside the flame, and that the flame was literally pushed away from the burner and put out.
It’s too early to say how well the effect will scale to larger flames. Cademartiri said he and his colleagues have begun collaborating with the U.S. Naval Research Laboratory in Washington, D.C., which has facilities devoted to the study of fire.
“I’m very optimistic that something very relevant is going to come out of this new capability,” he said.
More efficient energy?
The most obvious effect is fire suppression. But there are other applications as well. The world still derives about 90 percent of its energy from burning coal, natural gas and other products.
The potential to better control the internal flow of combustion could lead to more efficient energy production, among other benefits.
“Our hypothesis was that if we could find any new way to control flames in a novel way, we have a real chance to make a real big impact,” Cademartiri said. “This is our hope.”
I know a guy who built an audio amplifier using a home-built plasma triode. Made with a bunsen burner.
So now the municipal fire department can close shop in favor of the International Brotherhood of Electrical Workers?
Very interesting - I’d like to read more on this!
Yea, I remember looking at the flicker from candles while listening to music. Far out!
Maybe they could build a flamethrower that can shoot balls of fire at a good distance, sort of like photon torpedoes. I would need one of these for shooting squirrels in my backyard.
“Since the time humans first began to control fire around 400,000 years ago...”
Would love to see a source to back this up.
Fantastic fire haarp into forest fires let’s give it a real whirl
“Since the time humans first began to control fire around 400,000 years ago...”
Would love to see a source to back this up.
Fire trucks and their electric wands will be common some day?
But how does it work? Cademartiri acknowledged that the phenomenon is complex with several effects occurring simultaneously. Among these effects, it appears that carbon particles, or soot, generated in the flame are key for its response to electric fields. Soot particles can easily become charged. The charged particles respond to the electric field, affecting the stability of flames, he said.
“Combustion is first and foremost a chemical reaction – arguably one of the most important – but it’s been somewhat neglected by most of the chemical community,” said Cademartiri. “We’re trying to get a more complete picture of this very complex interaction.”
Cademartiri envisions that futuristic electrical devices based on the phenomenon could be fixed on the ceilings of buildings or ships, similar to stationary water sprinklers now in use. Alternatively, firefighters might carry the flame-tamer in the form of a backpack and distribute the electricity to fires using a handheld wand. Such a device could be used, for instance, to make a path for firefighters to enter a fire or create an escape path for people to exit, he said.
The system shows particular promise for fighting fires in enclosed quarters, such as armored trucks, planes, and submarines. Large forest fires, which spread over much larger areas, are not as suitable for the technique, he noted.
Cademartiri also reported how he and his colleagues found that electrical waves can control the heat and distribution of flames. As a result, the technology could potentially improve the efficiency of a wide variety of technologies that involve controlled combustion, including automobile engines, power plants, and welding and cutting torches, he said.
###
The Defense Advanced Research Projects Agency (U.S. Department of Defense) and the U.S. Department of Energy funded this study.
http://wildfiretoday.com/2011/03/28/fight-fire-with-an-electric-wand/
I know for a fact it was 400,001 years ago.
I am thinking that a p.o. squirrel running around the outside of your house with his tail on fire is not a good thing.
Very interesting..It is. Wondering how practical it may be. Where does the fire triangle get broken? Heat, oxygen and fuel?
A well-known effect in night clubs with loud sound systems. They call it “bassing” the candles. (long “a” sound)
Plasma flame triode: http://www.sparkbangbuzz.com/flame-amp/flameamp.htm
I didn’t know Harvard still did some hard science, I doubt this is in the 15th Century Romanian Feminist Philosophy Course.
lol
Wikipedia probably.
Fire was used by Homo erectus in northern China more than 400,000 years ago, and there is sketchy evidence suggesting that it may have been used long before that (Gowlett, 1984, pp. 181-82).
http://www.dieoff.org/page137.htm
"...field created an organized “flow” of charged particles inside the flame, and that the flame was literally pushed away from the burner and put out."
It seems like the flame is separated from the fuel when the charged particles line up and the flame is either separated by being pushed away or allowed to waft up separate from the fuel source? Not really sure.
You can also make a loudspeaker out of an acetyline flame—my fellow engineering students would do this at our annual open house.
Then there was the “Ionovac” tweeter, marketed by DuKane and Electro-voice. No diaphragm, just a small volume of ionized gas. You used it for frequencies above several kilocycles, and had a top end for dogs and bats.
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