Fighting Fire with Electrically Assisted Wind

Prototype Aerosol Launcher (Image: Ohio State University)

Researchers have developed a new portable tool that could improve how firefighters douse fires, making the process more efficient and far less risky.

Built as an alternative to traditional firefighting countermeasures like toxic chemical foams or hydrants whose use can strain water resources, this device works to suppress flames using the power of conductive aerosols, small particles that can direct electricity.

These aerosols are carried by vortex rings — small donut-shaped bands of air — that transform the particles into short pulses of wind that convert nearby oxygen into ozone. Once released, their accelerated airflow generates rapid turbulence, disrupting the natural combustion process and quickly extinguishing the target fire, said Lead Author John LaRocco, Research Scientist in Psychiatry at The Ohio State University College of Medicine.

“Using a combination of electricity and this vortex ring technology, we found a more efficient way of solving an environmental problem that will improve our quality of life,” said LaRocco.

The launcher device resembles a small bucket, attached to an arm brace. Firefighters would aim the bucket toward the fire, and the bucket would use bursts of compressed air or an elastic diaphragm to deliver aerosols in an electric arc to fight the fire.

The idea to create this low-cost, safe and portable device originally began as a method to help refine current fire management techniques, said Co-Author Qudsia Tahmina, Associate Professor in Electrical and Computer Engineering.

Here is an exclusive Tech Briefs interview, edited for length and clarity, with LaRocco, Tahmina, and Co-Author John Simonis, Undergraduate Student, Electrical and Computer Engineering.

Tech Briefs: What was the biggest technical challenge you faced while a developing this launcher device?

Simonis: We had two major challenges that really stood out for this project. The first one was the aerosol testing that we had to do: trying to figure out which aerosol was most effective with our ionic wind idea. That posed a substantial challenge because there are essentially an infinite number of mixtures of different types of aerosols that we could test. Luckily for me, I already had another student, [Co-Author] Stanley Essel, who went through a great deal of testing to sort out some of the options that were not so good from some that were good. Then I was able to further reiterate on that testing with a few more options, testing stuff like gold leaf foil, copper leaf foil, silver leaf foil, shredded, fine shredded, and long strands, etc.

From left to right: John LaRocco, John Simonis, and Qudsia Tahmina. (Image: Ohio State University)

Another challenge was the data analysis, because we ended up having over 200 images or so by the time this project was over. All of the data that we had to extract for this project for analysis had to come from these pictures. So, I ended up having to write a script using a Python library called Open CV or Open Computer Vision.

After we had all that data running through the script, I was able to carefully go through each individual image and make sure all the data was correct. But, even with the script, it took a lot of time.

Tech Briefs: Can you explain in simple terms how it works?

LaRocco: We use kinds of blind smoke rings carrying conductive chemicals to extend the length of the electric discharge, and use that to potentially ionize the air to generate turbulence. Because vortex rings themselves are full of turbulent air, switching that around can help potentially magnify the efficiency of the non-toxic chemical-based extinguishing.

Tahmina: It's kind of like a tornado. If you think about a tornado, it brings in the outside air and energizes the field inside of it. We call it the eye of the tornado. So, pretty much same concept here.

Simonis: One of the other challenges that we had was figuring out the most effective shape for generating those vortex rings. So, we ultimately ended up using an open-source library called Fluid X3D, which is computational fluid dynamics (CFD) software, to test different mesh shapes of our vortex spring launcher to find the best nozzle shape for generating a vortex ring for our project.