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mulanrootoday at 2:40 AM3 repliesview on HN

The reason this keeps getting reinvented is that the physics only half works. Sound disrupts the flame's boundary layer and separates it from the fuel, but it removes almost no heat. The fuel stays above its ignition temperature, so anything hot nearby relights it the second the speaker stops. DARPA demoed this in 2012 and it stalled there. Impressive on a small liquid fuel fire in a lab, very hard to scale to anything you'd actually want to put out.


Replies

pmontratoday at 6:18 AM

Yes, I kind of discovered that in a dream, in which I extinguished a fire by teleporting away oxygen. It worked, until I stopped teleporting. The oxygen came back and the fire started again. When I eventually woke up I thought about it and I told to myself that I should have chilled the place, not that it matters in real life. I was also proud of my subconscious' understanding of physics.

rkagerertoday at 3:39 AM

I wonder if one could use a thermal camera (or some other, high speed sensor) and some kind of feedback loop to squelch it and keep it disrupted until it cools. Or conversely, manipulate the flame for more complete combustion (in industrial processes).

But granted, I have trouble seeing this work on a large scale without much more sophisticated sonic wave tech.

katatuetoday at 6:47 AM

Same application spectrum as CO2 fire extinguishers I'd imagine (which we use for expensive lab hardware that we don't want to get damaged by water, foam, ..., but which are utterly useless for anything more substantial becuase it just reignites).