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# Fight Fire with Sound

The Objective

In my project, I wanted to tackle the question: How do you extinguish a fire in space? In electrical or electronic control panels? In an aircraft or a submarine? This is a tricky question as traditional extinguishers do not work in micro-gravity environments, and are messy and they run out. The answer: Sound! I discovered that using sound pressure waves, one can extinguish a sizable flame. I wanted to examine the interactions between sound waves and fire. I wanted to determine which frequency would be most effective in extinguishing a constant flame from a Bunsen burner. This can be used to further study engineering applications for extinguishing fire.

Methods/Materials

In my quest to extinguish fire with sound, I used a ½ inch Bunsen burner, in front of a 12 inch subwoofer, connected to a variable tone generator.

Adjacent to that was a scaled board from which to read data.

I had run tests in increments of 10Hz from 120Hz to 10Hz at different distances repetitively.

Filming the flame was a camera, with a feed to my computer.

This camera provided data as to the vertical deflection of the flame.

Using this data, I determined the optimal firefighting frequency.

Results

Through my testing and research, I have concluded that 40 Hz is the optimal frequency for extinguish a flame width of ½ inch.

I have also concluded that the closer the flame is to the sound source, the more powerful the sound wave is, therefore instantly extinguishing the flame.

I noticed that the optimal frequency is related to the width of the flame.

I also tested higher frequencies, which had no appreciable effect on the flame.

The range of 20-40 Hz and 50-70 Hz also deflected the flame then eventually, at certain distances, extinguished it.

Conclusions/Discussion

The idea of extinguishing fire with sound can be a novel one, however, it is efficient and effective, and has many possible applications in todays world. For instance, installed in every electrical control panel, can be mounted a subwoofer on a dedicated circuit, designed to turn on whenever fire is detected. It can be programmed to alternate the frequency based on the width of the flame. The effectiveness of a certain frequency needs to be in proportion with the width of the flame. With many possible applications, fighting fire with sound is a promising venue, in which sound pressure waves can be used to save an important control center, or an astronauts life.

My project is about using sound pressure waves to extinguish fire.

Science Fair Project done By Edward J. Kronfli