[Stoves] Trials on TLUD Gas Burners - Counter Current Flow

Julien Winter winter.julien at gmail.com
Tue Aug 5 00:41:17 CDT 2014


Hello Stoves;

Kirk commented in this thread that he thought that my Burner #1 (were I
simply inserted a cylindrical chimney into the mouth of a TLUD) didn't work
well because it was deficient in secondary air.

My though on this was that the burner was too narrow to allow the flame to
expand properly.  However, Kirk is no fool, so I kept thinking on why the
difference in opinion.  Then, it occurred to me that I may have a scaling
problem.  My tin can models may not be performing the same way as a full
sized stove.

So, I decided to use a burner somewhat like Burner #1 on a 7-inch diameter
TLUD.  Look what happened:
http://youtu.be/RnVaHpLZg8U


The TLUD was running with a 15% open grate for primary air, so gasification
of dry wood chip fuel was fast, and the gas flame large and rowdy.  All the
same there was no visible smoke as I had seen with the smaller prototype.
At full power that flame needs work to see if I can reduce its height.  I
may need to add secondary air holes higher up the burner (which goes
against one of my assumptions).  There certainly is a lot of scope for
turndown.

What was really interesting was that the char on the top of the fuel bed
remained hot, and when the gas flame went out, I had char gasification on
both the top and the bottom.  This burner could prevent the fuel bed
temperature from dropping above the pyrolysis front, and that could improve
combustion efficiency.

That tin can models don't always perform as full scale stoves was not
unexpected.  The small models are very good for preliminary testing of
hypotheses.  In the end, however, the work has to be corroborated at full
scale.

Thanks Erin, for fixing the links.

Thanks Martin for the link to the DEOM-stove and the suggestion to
sculpture the secondary air intake.  That may be most easily done to the
bottom of the chimney.

Thanks, also to Ron for his comments.  One thing is for sure.  When
gasifiers start to be made on 3-D printers, it will require some very
sophisticated computer modeling.  I don't expect that the result will look
anything like the stoves we know today.  But will they cost $5?

Cheers,
Julien.




-- 
Julien Winter
Cobourg, ON, CANADA
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