[Stoves] tuning a new stove

[David Young]

On Tue, Mar 25, 2014 at 04:51:34PM -0500, David Young wrote:
> I have been thinking about the variables that I can adjust to improve
> the stove's performance, and there are a lot: I can add more secondary
> air holes (or try to plug some up), remove the secondary-air preheater,
> shorten the preheater, create a gap between the primary chamber and the
> secondary with a wire, extend the chimney by a few inches above the
> preheater, etc.  Any advice what to try, first?

I found a little time to test this evening.  Performance was a lot like
last night: a blue flame with yellow tips formed and grew taller.  The
flame went out and spontaneously re-lit a few times.  Eventually the
interval between losing flame and re-lighting grew long enough that the
stove was without flame more often than not, and I started re-lighting
with a match.

Suspecting that the wood gas was overwhelming the secondary air and
putting out the flame, I closed the primary air aperture completely.
Then I added a chimney about two inches tall (made from a bit of
18-ounce can leftover from constructing the stove).  That stabilized the
flame for a while.  I found that removing the chimney had a dramatic
effect: where previously the flame licked the top of the chimney, it
receded into the combustion chamber when I took the chimney off.

I have noticed that the flame is diffuse at the bottom of the combustion
chamber, but it forms a narrow tube or a ribbon before it exits the
chamber.  It seems like I should strive to break that tube/ribbon up and
shorten the combustion zone by adding air, mixing turbulence, or both.

Dave

-- 
David Young
dyoung at pobox.com    Urbana, IL    (217) 721-9981