Fire in space

[Brian G Turner]

A couple of short videos showing that fire burns as a sphere in the absence of gravity:

If anyone knows any more, feel free to post them up here.

 

[RJM Corbet]

Ok: well soot is unburned carbon from the hydrocarbon fuel. So a candle flame is incandescent carbon yellow and sooty. Blow in air and the soot is increasingly burned up to make carbon dioxide. There is an increase in heat; the flame becomes bluer and hotter. Light energy changes to heat energy.

However air is 80% incombustible nitrogen: it's the 20% oxygen that is needed to assist combustion. So if you keep adding air, you end up adding too much nitrogen and that will end up cooling the flame.

Extract the oxygen from the air and add pure oxygen to the fire and you will end up with full combustion and a very hot blue flame.

Although an air/gas flame is blue, it is not nearly as hot as an oxy/gas flame -- which can end up oxidizing the nitrogen from the surrounding air as well, to form nitrous oxide, in a closed space not good.

EDIT: normally combustion products would disperse away from the combustion area, but perhaps without gravity they do not, so ... ?

 

[tinkerdan]

https://www.basicknowledge101.com/photos/2017/flamezerogravity.jpg

 

[RJM Corbet]

https://www.basicknowledge101.com/photos/2017/flamezerogravity.jpg

Cool! So I looked up the explanation:

Strange Flames on the ISS | Science Mission Directorate

Researchers experimenting with flames onboard the International Space Station have produced a strange, cool-burning form of fire that could help improve the efficiency of auto engines.

science.nasa.gov

Always learning something new here