Fighting out of control fires could become faster and more eco-friendly with an unusual technique that snuffs out flames using blasts of electrical waves. The discovery could underpin a new genre of fire-fighting devices, including sprinkler systems that suppress fires not with water, but with zaps of electric current, without soaking and irreparably damaging the contents of a home, business, or other structure. Reporting at the 241st National Meeting & Exposition of the American Chemical Society (ACS), Ludovico Cademartiri, Ph.D., and his colleagues in the group of George M. Whitesides, Ph.D., at Harvard University, picked up on a 200-year-old observation that electricity can affect the shape of flames, making flames bend, twist, turn, flicker, and even snuffing them out. However, precious little research had been done over the years on the phenomenon.
Firefighters currently use water, foam, powder and other substances to extinguish flames. The new technology could allow them to put out fires remotely — without delivering material to the flame — and suppress fires from a distance. The technology could also save water and avoid the use of fire-fighting materials that could potentially harm the environment, the scientists suggest.
In the new study, they connected a powerful electrical amplifier to a wand-like probe and used the device to shoot beams of electricity at an open flame more than a foot high. Almost instantly, the flame was snuffed out. Much to their fascination, it worked time and again.
The device consisted of a 600-watt amplifier, or about the same power as a high-end car stereo system. However it is believed that a power source with only a tenth of this wattage could have similar flame-suppressing effect. That could be a boon to firefighters, since it would enable use of portable flame-tamer devices, which perhaps could be hand-carried or fit into a backpack.
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.
This study was funded by The Defense Advanced Research Projects Agency (U.S. Department of Defense) and the U.S. Department of Energy.
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