[Stoves] Down with Fantasy-draft stoves

alex english aenglish444 at gmail.com
Sat Mar 24 12:11:59 CDT 2018


Paul,
Lacking anything like data backed proof of down-drafting  in these little
stoves without fans. I say no way.

Buoyancy in chimneys and stoves is often visualized as something like
gasses, being sucked up. It is really gasses being pushed up by heavier
gasses being sucked down by by gravity more like water seeking it own level
and forcing air above it. Inside a top lit stove of pellets the air in the
bottom is cold and heavy. It is pushed up to replace the lighter hot gasses
above. Edge of container  effects may cause small eddies. If it is cooler
than the hot middle then a bit of down movement but not much. As the
container heats up it may be hotter than the cool pellets in the middle.
Then there would be a little movement up near the edge. The end result in a
TLUD is a fire or front (MPF) that in fact seeks its own level.

I have operated  Paul brand TLUD in a painted cylinder filled with pellets
so slowly that the pellets at the edge were torrified and the rest were
charred and the paint was still good.  I have operated pellets at 18 inches
in diameter , 40 inches deep for up to a continuous burn of 12 hours. I
have also operated continuous down drafters for days but needed a hot 10
feet of chimney to over come buoyancy in a two inch diameter burner.

There's no pressure gradient to drive this fantasy in the real world.

Ah there's Hugh now....driving his own spike.

Done

Alex
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