Astronomy Question: Smoke and Fire in Zero-g?
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Markus asks:
“Dear Astronomer, Imagine you are inside the space station, with all fans and air circulation turned off.
The air inside is completely still. You decide to light a cigarette.How would the smoke from the burning cigarette form? Would it be a perfect sphere?
Would the smoke around the cigarette kill off the oxygen supply and put the cigarette out,
or would the cigarette slowly float away like a small mini rocket?
Interesting question Markus!
NASA actually has been performing experiments on the International Space Station to learn more about how fire behaves in zero-g.
Read more to learn about what the NASA studies have revealed.
Color image of a burning fuel droplet. (NASA/GRC)
NASA’s Flame Extinguishment Experiment (FLEX), has performed over 200 tests in the past three years aboard the International Space Station. The goal of FLEX is to better understand the properties of flames, as well as the best ways to put out fires in zero-gravity environments.
On Earth, the heated gas rises from a fire, and draws oxygen into the flame. However, in zero-gravity environments, heated gases do not rise, so the process that drives the flame is molecular diffusion. The end result is that fires in space burn slower, cooler, and use less oxygen than on Earth.
Given the different behavior of fire, NASA must design fire-suppression methods that use higher concentrations of flame-retarding materials. One other concern with fire aboard a space station or craft orbiting Earth is that ventilation fans could the fire to accelerate.
How NASA’s FLEX helps researchers learn more about fire in zero-gravity is by igniting a small drop of heptane or methanol. The fuel droplet burns for less than a minute, and while doing so, a spherical flame is created. As the flame burns, the fuel droplet will shrink until all the fuel is burned up, or the flame is extinguished.
Here’s a video showing NASA’s FLEX in action. It’s not exactly a burning cigarette, but it’s still pretty amazing to watch.
In short, scientists are still learning how fire behaves in space, but current experiments, such as FLEX are helping us learn the answers.
Ray Sanders is a Sci-Fi geek, astronomer and blogger. Currently researching variable stars at Arizona State University, he writes for Universe Today, The Planetary Society blog, and his own blog, Dear Astronomer
2012-12-04 08:07:17
Source: http://www.dearastronomer.com/2012/02/10/astronomy-question-smoke-and-fire-in-zero-g/
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