Applying physics to put out a fire, as opposed to chemistry, is an idea DARPA has been eyeing for a while, and it might lead to military devices that can better snuff out fires in enclosed places. Now they have demonstrated a new device in action.
In the video, two speakers are placed on either side of a fuel source. The sound increases air velocity, which disrupts the flame. It also causes higher fuel vaporization, which increases the flame's area while dropping its temperature. That thinning causes a problem in the combustion process.