[Stoves] Seeking feedback on a mixed-materials TLUD

[Julien Winter]

Hello Bodie;

That is a very interesting TLUD stove you have made.

Colleagues of mine in Bangladesh are trying to do a similar thing.  Metal
is rather scarce in the countryside, and has to be imported at relatively
high expense (relative to the local economy).  There is a strong tradition
of clay stoves, and a lot of work by government scientists and NGOs to
design improved "Bondhu Chulas" made from cement and clay.  The more the
TLUD can be made from local materials, the better.

There are a couple of things you could try with your stove.

1)  The riser is too narrow and creates a tall diffusion flame.  Instead of
using the concentrator method, try increasing the diameter of the riser to
at least the same size as the TLUD reactor.    Where the secondary air
enters between the TLUD reactor and the bottom of the riser, create some
large groves in the clay so that secondary air enters as jets, rather than
as a continuous sheet.  I don't recommend that you angle the groves to
create a swirl, because that can create a taller flame, like a tornado;
also the TLUD will not turn down as well.   If you increase the diameter of
the riser, you will have more horizontal space for the gas flame to
expand.

2)  To get good turn down you need to control primary air to very low
levels.  For that you will need a good seal or seating between the TLUD
reactor and the surrounding clay base.   In my experience, the space for
primary air should be regulated between 1 and 15% of TLUD cross-sectional
area.  Most of the turndown is between 1-3% area.  Paul Anderson's
"Champion Stove" has a good way of controlling primary air by making the
entrance for the air a cone-shaped hole, with the large end facing
outwards.  To control the air, a solid cone-shaped plug is moved into the
cone-shaped hole.    I can't say that I have given much though to
controlling primary air yet, so you may get alternate suggestions.

Thanks for sending the pdf of your stove.  I will forward it to Bangladesh
to give my pals some encouragement.

All the best,
Julien.

-- 
Julien Winter
Cobourg, ON, CANADA
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