In the study, researchers connected an 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. The device consisted of a 600-watt amplifier, about the same power as a high-end car stereo system, but they believe that a power source with only a tenth of that wattage could have similar flame-suppressing effect. For firefighters, that means portable flame-tamer devices, hand-carried or in a backpack.
How does it work? Reporting at the National Meeting&Exposition of the American Chemical Society, 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.
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.