Re: What Flows?

["Paul Camp" <pjcamp@coastal.edu>]

> By the way, what do flames in zero g environments do?  I suppose that they
> aren't spherically symetric, since air needs to get into them for fuel.  Is
> that right?  Do they sputter?
>
> -- 
> --James McLean

In microgravity, the flow of air into the flame due to 
buoyancy-driven convection is absent. The fire is sustained only by 
the oxygen that it consumes as it migrates along the fuel's surface. 
This experiment was done on the space shuttle a while back and it was 
observed that fuel not consumed during the initial spreading of the 
flame burned sporadically thereafter. Since there are no convection 
currents, the flame shape _is_ in fact spherical and a great deal 
dimmer and bluer than a corresponding flame on Earth. The flame does 
tend to oscillate a bit and, if you bring an unlit candle near it, 
will for some obscure reason become asymmetric and rotate before 
going out. Also, it is difficult to impossible to light the second 
candle due to deficiency of oxygen presumably, the exact opposite of 
what would be the case on Earth.



Paul J. Camp                   "The Beauty of the Universe
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