Fire in microgravity

"JotaCe" wrote in message
oups.com...
I have been thinking about the way the fire behaves in microgravity. I
have found little information on this in the internet, so I am mostly
just wondering, and these thoughts are what I want to share with you
for discussion:

In absence of gravity, the flames create a sort of sphere around the
core of the fire (of course, this sphere will be limitated by the
object in fire; depending on its shape, we will have an almost entire
ball for a match, or just a semi-sphere in the case of a fire on a flat
surface). Well, if the core of the fire is surrounded by flames
(incandescent gases), how can the core be feed by fresh oxygen to keep
the fire burning? Maybe this creates a sort of pulsating effect on the
spherical flame, contracting it when the oxygen is running out, and
allowing thus the flux of more oxygen into the core, which feeds again
the flames to its previous size?

If someone knows where can I find more information on this matter, I
would be very grateful. Best regards,

Javier Casado
Space stuff in spanish in: http://es.geocities.com/fjcasadop

If heat cannot rise and draw in cool oxygenated air from the bottom it seems
to me that the fire would tend to smother itself.

"Nog" :

If heat cannot rise and draw in cool oxygenated air from the bottom it
seems to me that the fire would tend to smother itself.

You would think so, however in freefall the flame develops lots of free
radicals in the volume the flame occurs in. Thus even if the flame seems to
die out as soon as oxygen makes it into the flame zone the radicals will
burn, releasing heat that causes more free radicals to form. There is a lot
more than this going on, but that should give you an idea why the fire never
really goes out.

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
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the time? http://webhome.idirect.com/~earlcp

The flame itself is much smaller, and oxygen can easily permeat the flame
zone. The rate of permeation is what limits the size of the flame. The
lack of convection allows the reduced combuston rate to sustain the
temperatures necessary to maintain the reaction. The flame itself can burn
much hotter as a result of the lack of convection, since the primary loss of
heat is limited to radiation.

"JotaCe" wrote in message
oups.com...
I have been thinking about the way the fire behaves in microgravity. I
have found little information on this in the internet, so I am mostly
just wondering, and these thoughts are what I want to share with you
for discussion:

In absence of gravity, the flames create a sort of sphere around the
core of the fire (of course, this sphere will be limitated by the
object in fire; depending on its shape, we will have an almost entire
ball for a match, or just a semi-sphere in the case of a fire on a flat
surface). Well, if the core of the fire is surrounded by flames
(incandescent gases), how can the core be feed by fresh oxygen to keep
the fire burning? Maybe this creates a sort of pulsating effect on the
spherical flame, contracting it when the oxygen is running out, and
allowing thus the flux of more oxygen into the core, which feeds again
the flames to its previous size?

If someone knows where can I find more information on this matter, I
would be very grateful. Best regards,

Javier Casado
Space stuff in spanish in: http://es.geocities.com/fjcasadop