Fire and Zero G

[brandbll]

If you were in the space shuttle and lit a match what would happen with the flame from the match? I.e. what direction would it go?

 

[nimbus]

I think there's a pretty popular picture out there from an ISS candle. It looks spherical. A less regular combustible like a randomly shaped spill of oil might look funkier.

Here it is.
http://science.howstuffworks.com/space-station5.htm

 

[Woggles]

Just adding to the post

Question: Can you describe in words how fire appears in a zero-G environment?

From Erik in Bloomington.

Answer: I think I am the astronaut extraordinaire when it comes to fire. We had an actual fire on board Mir, about a three-foot flame, melting metal. It lasted about 14 minutes, smoke billowing out—a very, very dangerous situation. I also observed fire inside a controlled glove box which isolated the smoke and flame from the rest of the space station. And fire behaves somewhat differently than it would down on the ground. For example, a flame is not flame-shaped. It's not a teardrop; it is a sphere in space. Also, you need to get air moving around a fire in order to feed the fire, and in space, because warm air does not rise, there is not a refreshing puff of fresh air coming into the base of the flame. And the flame will put itself out unless you have a fan or a wind tunnel, in the case of a controlled experiment, blowing air into the flame to provide the oxygen. So fire does behave differently in space, and in general, because of zero-gravity, a lot of things behave differently. It did feel funny.


from this link

http://www.pbs.org/wgbh/nova/mir/live.html


Also there is a book

http://books.google.ca/books?id=K9ZS7no ... ir&f=false

 

[SpaceTas]

There was a series of experiments on flames in space: spherical and tend to burn very low, both effects are due to lack of convection which is a direct result of the micro-gravity environment. This also makes fire hard to find, because the smoke/small is not wafted around by convective air currents.

Another example of the effect of a lack of convection: During Apollo 13 the astronauts could warm up when sleeping if they were very still. A thin layer of warm air would form all around them.

 

[Woggles]

Another example of the effect of a lack of convection: During Apollo 13 the astronauts could warm up when sleeping if they were very still. A thin layer of warm air would form all around them.

Thanks tas! I didn't know that!

 

[crazyeddie]

I think there's a pretty popular picture out there from an ISS candle. It looks spherical. A less regular combustible like a randomly shaped spill of oil might look funkier.

Here it is.
http://science.howstuffworks.com/space-station5.htm

In the absence of gravity, wouldn't a lit match, or any burning flame, eventually become choked by it's own combustion by-products, and go out?

 

[a_lost_packet_]

..In the absence of gravity, wouldn't a lit match, or any burning flame, eventually become choked by it's own combustion by-products, and go out?

Yes, that's part of it. The other is that convection isn't really helping to bring in more oxygen. So, a burning stick would choke itself to death and a match would slowly sputter out after the oxidizers are consumed. But, if there is any air movement, that effect is canceled out and the flame is sustainable. Having moving air, as one would find in a properly ventilated space station, is what keeps flames fed.

I'm not sure, but I seem to remember the ISS having slightly elevated levels of oxygen. Something to do with breathing efficiency/comfort or the like.