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<pre class="moz-signature" cols="72">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: <a class="moz-txt-link-abbreviated" href="mailto:psanders@ilstu.edu">psanders@ilstu.edu</a>
Skype: paultlud Phone: +1-309-452-7072
Website: <a class="moz-txt-link-abbreviated" href="http://www.drtlud.com">www.drtlud.com</a></pre>
<div class="moz-cite-prefix">On 3/24/2018 7:39 AM, Ronal W. Larson
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<div class="">Kirk et al</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>You
have it partially correct - but we are not talking about a TLUD.
There is no MPF (Moving Pyrolysis Front). Rather, the
pyrolysis gases are created by the downward flowing (very) hot
gases.. <br>
</div>
</blockquote>
Incorrect. There is no way for the very hot gases that are the
flame at the top to go downward WITH O2 through a substantial layer
of hot charcoal and then reach the raw biomass fuel at temperatures
that are going to cause full-fledged pyrolysis (at least above 400
C) and continue downward to exit through what are called "primary
air inlets" (but are claimed to be outlets).<br>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>Besides
N2, there is a fair amount of CO2 - but no O2. Much more gas
comes out the bottom than enters (all valuable pyrolysis gases)
. Possible only because of the Venturi effect - not iimportant
in TLUDs.</div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>See <a
href="http://www.charcoalproject.org/2010/05/a-man-a-stove-a-mission/"
class="" moz-do-not-send="true">http://www.charcoalproject.org/2010/05/a-man-a-stove-a-mission/</a>
.</div>
</blockquote>
My very quick look at this did not find speciic content about
proving the downdraft issue. (If anyone finds specific content,
please call it to my/our attention.)<br>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<div class=""><br class="">
</div>
<div class="">and:</div>
<div class=""><br class="">
</div>
<div class=""><a
href="https://foodtank.com/news/2017/05/nathaniel-mulcahy-worldstove-talks-clean-cooking-stoves/"
class="" moz-do-not-send="true">https://foodtank.com/news/2017/05/nathaniel-mulcahy-worldstove-talks-clean-cooking-stoves/</a></div>
</blockquote>
Also an Info item, not a science item. <br>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<div class=""><br class="">
</div>
<div class="">and </div>
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span><a
href="https://www.youtube.com/watch?v=QsH_Gh-n2Mg" class=""
moz-do-not-send="true">https://www.youtube.com/watch?v=QsH_Gh-n2Mg</a></div>
</blockquote>
This is the FORCED AIR Lucia stove and is not relevent to the
current conversation.<br>
<br>
See further down my reply to Noil (or was the Neil), and Crispin and
Kirk.<br>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<div class=""><br class="">
</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I
will look for more technical descriptions. Note these above
emphasize the biochar part of cooking.</div>
<div class=""><br class="">
</div>
<div class="">Ron</div>
<div class=""><br class="">
</div>
<br class="">
<div>
<blockquote type="cite" class="">
<div class="">On Mar 24, 2018, at 1:52 AM, Kirk H. <<a
href="mailto:gkharris316@comcast.net" class=""
moz-do-not-send="true">gkharris316@comcast.net</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div class="WordSection1" style="page: WordSection1;
font-family: Helvetica; font-size: 18px; font-style:
normal; font-variant-caps: normal; font-weight: normal;
letter-spacing: normal; orphans: auto; text-align: start;
text-indent: 0px; text-transform: none; white-space:
normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">All,</div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">I like
Noll’s remarks. If down-draft was occurring the gasses
would cool as they pass through the unburned fuel and so
the vapors would condense and become smoke. There would
be lots of smoke exiting the primary holes. This is not
happening in the video. Creosote would soon coat the
entire bottom and annulus portions of the stove and clog
the primary air openings. Creosote may also coat the
unburned fuel and so restrict the air flow. Also the
unburned fuel would get hotter and hotter and possibly
begin pyrolysing in mass.</div>
</div>
</div>
</blockquote>
</div>
</blockquote>
VERY good point. Something that can be studied via observation
without lots of expensive equipment.<br>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<div>
<blockquote type="cite" class="">
<div class="">
<div class="WordSection1" style="page: WordSection1;
font-family: Helvetica; font-size: 18px; font-style:
normal; font-variant-caps: normal; font-weight: normal;
letter-spacing: normal; orphans: auto; text-align: start;
text-indent: 0px; text-transform: none; white-space:
normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">Paul’s
question about how air would get to the MPF from above
is unanswered. The air would have to pass through the
flame. This may be possible because the flame is a gas
and gasses are permeable. But as the air passes through
the flame, the oxygen would get used up so only nitrogen
would descend into the fuel and the MPF would go out.</div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">Crispin
remarks that it would have to be an air restricted
situation for down-draft to occur and only around the
edges. This sounds true, and you would not get much
fire power in an air restricted situation. And remember
how TLUDs go out when turned down too much? Would
whatever this is have the same problem?</div>
</div>
</div>
</blockquote>
</div>
</blockquote>
Yes, such a flow is to be considered. I visualize it as a donut.
Primary air upward through the donut hole and then some pyrolytic
gases downward as an annulus (the sides of the donut. Also to be
studied.<br>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<div>
<blockquote type="cite" class="">
<div class="">
<div class="WordSection1" style="page: WordSection1;
font-family: Helvetica; font-size: 18px; font-style:
normal; font-variant-caps: normal; font-weight: normal;
letter-spacing: normal; orphans: auto; text-align: start;
text-indent: 0px; text-transform: none; white-space:
normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">With
adequate primary air to keep the MPF going, adequate
secondary air, and an open top the gasses inside would
be actively interacting with the outside atmosphere.
All the gases, including near the edge of the chamber
are hotter than the atmosphere and subject to rising via
buoyancy, although perhaps at different rates. <span
class="Apple-converted-space"> </span></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">It is
unlikely that it is down-draft. <span
class="Apple-converted-space"> <br>
</span></div>
</div>
</div>
</blockquote>
</div>
</blockquote>
CLARIFICATION: Downdraft has at least two meanings. One can be
the movement of gases, such as some pyrolytic gases moving downward
in the fuel column (what we are discussing). The other is as in a
downdraft gasifier there the hot gases exit the gasifier by going
downward THROUGH the bottom layer of red-hot (white hot) charcoal.<br>
<br>
So the wording could be It is unlikely that it is down-draft
[gasification] Which it is not in this case. OR <span
class="Apple-converted-space">It is unlikely that [there] is
down-draft [of some gases within the column of fue.]. (which is
what is being discussed.) <br>
<br>
NOTE: This is te the most vigorous TECHNICAL-BASED DISCUSSION on
the Stoves Listserv for quite some time. I like it!!<br>
<br>
Paul<br>
<span class="Apple-converted-space"> </span></span>
<blockquote type="cite"
cite="mid:52B40B05-5448-4683-A740-DD7A706C4D3F@comcast.net">
<div>
<blockquote type="cite" class="">
<div class="">
<div class="WordSection1" style="page: WordSection1;
font-family: Helvetica; font-size: 18px; font-style:
normal; font-variant-caps: normal; font-weight: normal;
letter-spacing: normal; orphans: auto; text-align: start;
text-indent: 0px; text-transform: none; white-space:
normal; widows: auto; word-spacing: 0px;
-webkit-text-stroke-width: 0px;">
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">Kirk H.</div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">Sent from<span
class="Apple-converted-space"> </span><a
href="https://go.microsoft.com/fwlink/?LinkId=550986"
style="color: rgb(149, 79, 114); text-decoration:
underline;" class="" moz-do-not-send="true">Mail</a><span
class="Apple-converted-space"> </span>for Windows 10</div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="border-style: solid none none;
border-top-color: rgb(225, 225, 225); border-top-width:
1pt; padding: 3pt 0in 0in;" class="">
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif; border: none;
padding: 0in;" class=""><b class="">From:<span
class="Apple-converted-space"> </span></b><a
href="mailto:psanders@ilstu.edu" style="color:
rgb(149, 79, 114); text-decoration: underline;"
class="" moz-do-not-send="true">Paul Anderson</a><br
class="">
<b class="">Sent:<span class="Apple-converted-space"> </span></b>Friday,
March 23, 2018 6:09 PM<br class="">
<b class="">To:<span class="Apple-converted-space"> </span></b><a
href="mailto:wastemin1@verizon.net" style="color:
rgb(149, 79, 114); text-decoration: underline;"
class="" moz-do-not-send="true">Hugh McLaughlin</a>;<span
class="Apple-converted-space"> </span><a
href="mailto:Stoves@lists.bioenergylists.org"
style="color: rgb(149, 79, 114); text-decoration:
underline;" class="" moz-do-not-send="true">Stoves
and biofuels network</a><br class="">
<b class="">Subject:<span
class="Apple-converted-space"> </span></b>Re:
[Stoves] Explaination of downdraft in TLUD updraft
stoves ---was --Re: Mis-information</div>
</div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class=""><o:p
class=""> </o:p></div>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">Hugh,<br
class="">
<br class="">
Thanks for the reply. I am forwarding it to the Stoves
Listserv. <span class="Apple-converted-space"> </span><br
class="">
<br class="">
The impact of the air being drawn in (creating a draft
onto the ignited stick) should be able to be checked by
shielding the flame from the direct draft.<br class="">
<br class="">
To all: How can we get copies of these messages to
Heath Putnam for his input?<br class="">
<br class="">
Paul<br class="">
<br class="">
<br class="">
<o:p class=""></o:p></div>
<pre style="margin: 0in 0in 0.0001pt; font-size: 10pt; font-family: 'Courier New';" class="">Doc / Dr TLUD / Prof. Paul S. Anderson, PhD</pre>
<pre style="margin: 0in 0in 0.0001pt; font-size: 10pt; font-family: 'Courier New';" class="">Email: <a href="mailto:psanders@ilstu.edu" style="color: rgb(149, 79, 114); text-decoration: underline;" class="" moz-do-not-send="true">psanders@ilstu.edu</a></pre>
<pre style="margin: 0in 0in 0.0001pt; font-size: 10pt; font-family: 'Courier New';" class="">Skype: paultlud Phone: +1-309-452-7072</pre>
<pre style="margin: 0in 0in 0.0001pt; font-size: 10pt; font-family: 'Courier New';" class="">Website: <a href="http://www.drtlud.com/" style="color: rgb(149, 79, 114); text-decoration: underline;" class="" moz-do-not-send="true">www.drtlud.com</a></pre>
<div class="">
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
font-family: Calibri, sans-serif;" class="">On
3/22/2018 5:41 PM, Hugh McLaughlin wrote:<o:p class=""></o:p></div>
</div>
<blockquote style="margin-top: 5pt; margin-bottom: 5pt;"
class="">
<div class="">
<div id="yui_3_16_0_ym19_1_1521756600094_10264"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class="">Paul,<o:p class=""></o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10270"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class=""><o:p class=""> </o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10389"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class="">I am unconvinced. One of
the comments (the first - Arthur Noll) provides
an explanation - it is the air being drawn into
the base (primary air inlets) that stimulate the
burning at the bottom.<o:p class=""></o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10542"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class=""><o:p class=""> </o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10543"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class="">Hugh<o:p class=""></o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10513"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class=""><o:p class=""> </o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10514"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class="">Noll's comment is copied
below:<o:p class=""></o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10390"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class=""><o:p class=""> </o:p></span></div>
</div>
<div id="yui_3_16_0_ym19_1_1521756600094_10503"
class="">
<div style="margin: 0in 0in 0.0001pt; font-size:
11pt; font-family: Calibri, sans-serif;
background-color: white;" class=""><span
style="font-size: 10pt; font-family: Verdana,
sans-serif;" class="">That is interesting, but
I'm not convinced that pyrolysis products are
coming out of the bottom. You don't see any
smoke coming out the bottom until you put the
flaming stick in there. The stick could be
producing the smoke that hits the bottom of the
can, turns sideways and joins the flow of air,
much of which is rising up the sides between the
containers, while smaller amounts are going in
to the wood. If it were correct that products
of pyrolysis were going down and then up, I
would expect to see a significant amount of
smoke coming out the bottom and up the sides all
the time, not just when the stick was put in.
And I would expect to see soot and tar
precipitating out on the surfaces between the
containers. Pyrolysis produces a combination of
gases, smoke, soot and tar. It is messy. I have
built these stoves and this area is always
clean, even after many burns, just like what
you have is clean. I have always felt that the
smoke, tar and gas from the pyrolosis was rising
up, and the preheated air coming out the
secondary air holes, going into this mixture of
flammable gas and vapor, made the jets of flame.
I don't think it makes any difference whether
you have a jet of air going into a mass of
flammable gas or if you have a jet of flammable
gas going into a mass of air, both can give you
a jet of flame.<span
class="Apple-converted-space"> </span><o:p
class=""></o:p></span></div>
</div>
<div class="">
<p class="MsoNormal" style="margin: 0in 0in 12pt;
font-size: 11pt; font-family: Calibri, sans-serif;
background-color: white; background-position:
initial initial; background-repeat: initial
initial;"><span style="font-size: 10pt;
font-family: Verdana, sans-serif;" class=""><o:p
class=""> </o:p></span></p>
</div>
<div class="">
<div class="">
<div class="">
<div class="">
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; background-color: white;"
class=""><span style="font-size: 10pt;
font-family: Arial, sans-serif;" class="">On
Thursday, March 22, 2018 9:05 AM, Paul
Anderson<span
class="Apple-converted-space"> </span><a
href="mailto:psanders@ilstu.edu"
style="color: rgb(149, 79, 114);
text-decoration: underline;" class=""
moz-do-not-send="true"><psanders@ilstu.edu></a><span
class="Apple-converted-space"> </span>wrote:</span><span
style="font-size: 12pt; font-family:
Helvetica, sans-serif;" class=""><o:p
class=""></o:p></span></div>
</div>
<p class="MsoNormal" style="margin: 0in 0in
12pt; font-size: 11pt; font-family: Calibri,
sans-serif; background-color: white;
background-position: initial initial;
background-repeat: initial initial;"><span
style="font-size: 12pt; font-family:
Helvetica, sans-serif;" class=""><o:p
class=""> </o:p></span></p>
<div class="">
<div id="yiv9198720191" class="">
<div class="">
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; text-align: center;
background-color: white;" class=""><b
class=""><span style="font-size: 14pt;
font-family: Helvetica, sans-serif;"
class="">Explanation of downdraft in
the fuel chamber of TLUD (UP draft)
stoves.</span></b><span
style="font-size: 12pt; font-family:
Helvetica, sans-serif;" class=""><o:p
class=""></o:p></span></div>
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; text-align: center;
background-color: white;" class=""><span
style="font-size: 12pt; font-family:
Helvetica, sans-serif;" class="">Paul
S. Anderson, PhD 21 March 2018<o:p
class=""></o:p></span></div>
<div class="">
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; background-color: white;"
class=""><span style="font-size: 12pt;
font-family: Helvetica, sans-serif;"
class="">Stovers, Previously I
wrote:<br class="">
*******************<br class="">
This link takes you to [what I am
calling Video A.)<br class="">
<a
href="https://www.youtube.com/watch?annotation_id=annotation_1962734105&feature=iv&src_vid=wzN-cYR84_Y&v=b0vM9aD78XY"
target="_blank" style="color:
rgb(149, 79, 114);
text-decoration: underline;"
class="" moz-do-not-send="true">https://www.youtube.com/watch?annotation_id=annotation_1962734105&feature=iv&src_vid=wzN-cYR84_Y&v=b0vM9aD78XY</a><br
class="">
Same fellow. and showing clearly
UPdraft. Side by side
comparisons. Well worth watching. <span
class="Apple-converted-space"> </span><br
class="">
That is dated 2015. I hope that
somebody will delve into this
further.<o:p class=""></o:p></span></div>
</div>
<div class="">
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; background-color: white;"
class=""><span style="font-size: 12pt;
font-family: Helvetica, sans-serif;"
class="">*****************************<o:p
class=""></o:p></span></div>
</div>
<div class="">
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; background-color: white;"
class=""><span style="font-size: 12pt;
font-family: Helvetica, sans-serif;"
class=""> First, we all should thank
Heath Putnam for his research and
for reporting it publicly. He also
provided an earlier video that lh
cheng saw and called to our
attention:<br class="">
<span class="Apple-converted-space"> </span><a
href="https://www.youtube.com/watch?v=wzN-cYR84_Y" target="_blank"
style="color: rgb(149, 79, 114);
text-decoration: underline;"
class="" moz-do-not-send="true">https://www.youtube.com/watch?v=wzN-cYR84_Y</a> <span
class="Apple-converted-space"> </span><o:p
class=""></o:p></span></div>
</div>
<div style="margin-bottom: 12pt;" class="">
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; background-color: white;"
class=""><span style="font-size: 12pt;
font-family: Helvetica, sans-serif;"
class="">This I am calling Video B.
Although dated earlier, it is better
to watch Video A first.<br class="">
<br class="">
After sleeping on this question last
night, I think I have an
explanation. And it also would
explain what Nate Mulcahey presented
as the "Everything Nice Stove" which
he claimed was not a TLUD stove and
claimed to be a downdraft flow of
the pyrolytic gases (or Opposite
draft). Putnam's work shows (but
does not explain) the answers about
downdraft in updraft TLUD stoves. <span
class="Apple-converted-space"> </span><br
class="">
<br class="">
The big clue (revealed in video (A)
above) is the difference between the
two trial units. The difference is
a sealed bottom that enables a
"co-mingled air supply zone" for
somewhat restricted primary and
secondary air versus abundant
secondary air that arrives
separately from the supply of
primary air. <span
class="Apple-converted-space"> </span><br
class="">
<br class="">
If the primary air entry is direct
or very nearly direct and sufficient
even with a small, restricted flow,
it will sustain the migratory
pyrolytic front (MPF), and all the
air and gases will flow upward.
This is the CLASSIC description of
TLUD operation.<br class="">
<br class="">
But consider the case of a
TLUD-design stove that has a closed
bottom (or is sitting reasonably
tightly on a flat surface that
prevents entry of abundant air) AND
also has somewhat limited entry (via
4 holes in Putnam's glass outer
cylinder) of air for<span
class="Apple-converted-space"> </span><b
class=""><u class="">BOTH<span
class="Apple-converted-space"> </span></u></b>primary
and secondary air into a space (a
"co-mingled air supply zone") from
which BOTH types of air must be
drawn. Therefore, the only exit is
upward. The only DRAFT for the
stove is powered by the flame of the
burning gases at the top. <span
class="Apple-converted-space"> </span><br
class="">
<br class="">
Consider the case of a functioning
TLUD stove when the MPF is below a
layer of charcoal about 3 to 6 cm
down from the top, with another 7 to
12 cm of raw fuel below the MPF.
The pyrolysis occurs, and the hot
gases tend to rise upward through
the layer of char and into the zone
of the cooking flame. But the
flame requires secondary air, which
can only come up in the ring
(annulus) between the two cylinders,
and it does come up. This is the
vast majority of the total supply of
air (about 5 units for secondary to
1 unit of primary air). In fact,
that natural draft by the flame is
pulling the air from the "co-mingled
air supply zone" (that one place of
air supply which is also feeding the
primary air). There is therefore a
reduction of air pressure below the
MPF, and that means less movement of
the primary air upwards. <span
class="Apple-converted-space"> </span><br
class="">
<br class="">
The result is that there is
sufficient lower pressure that SOME
of the pyrolytic gases move
downward. Probably some swirling
also, or some channels of gases
going down but with SOME (at least
some) primary air (the O2 is the
important part) moving to the MPF. <span
class="Apple-converted-space"> </span><br
class="">
With a little bit of time, some of
the pyrolytic gases reach the entry
holes of the primary air and leak
outward into the "co-mingled air
supply zone" where there is fresh
air entering and where those gases
can be combusted (as shown in the
Putnam demonstration in Video B).
Impressive. And if there is no
flame down there, those pyrolytic
gases can be pulled upward to become
part of the upward flowing secondary
air THAT IS NOW PRE-MIXED (-but
rather diluted to some unknown
amount -) WITH COMBUSTIBLE GASES.
Nice trick, and you can see Putnam's
demonstration of a taller, stronger
flame (Video A). This is
important. Pre-mixing is to be
encouraged. But it should be
understood and done intentionally to
attain consistent results. <span
class="Apple-converted-space"> </span><br
class="">
<br class="">
BUT in the described simple setup,
production of the pyrolytic gases is
suffering. There is a somewhat
deficiency of primary air. That
could be forgiven (or overlooked or
ignored) except for one very
important factor:<br class="">
<br class="">
When the downdraft is occurring, the
stove user loses some control over
the fire. The draft from the
burning gases is now regulating (in
part) the operations of the TLUD
stove. The normal control of a TLUD
fire is by closing off some primary
air, or using a small fan, but these
are no longer as effective because
of the co-mingled air. As the
flame at the top changes when there
is downward flow (shown by Putnam),
there is a ripple effect to the air
flows. Adjust, then adjust again,
and then adjust again. <span
class="Apple-converted-space"> </span><br
class="">
<br class="">
You can look at the Champion TLUD
(only one hole for primary air
entry) or the Quad or the Troika (by
Awamu) with only one entry for
primary air, or some of the other
more established true TLUD stoves.
The Peko Pe by Wendelbo also keeps
the two air sources separate.
Then look at Putnam's variation and
at the Everything Nice stove and see
how the primary and secondary air
are comingled and subjected to the
draft created at the top of the
stove.<br class="">
<br class="">
Also consider what would happen if
there actually was sufficient
downward draft for the FULL reversal
of the air flow in the fuel
chamber. At the top there is
flame. And how is there any O2
surviving in that flame so that it
could go downward enough to go
through the 3 to 6 (and deeper)
layer of hot charcoal in order for
O2 to reach FROM ABOVE the top side
of the MPF and to sustain that MPF
for sending gases further downward?
And then those pyrolytic gases would
need to go out through what were the
primary air inlet holes, and then be
mixed with secondary air (but never
catching fire because somehow there
was not a spark there, even at the
end of the batch with red-glowing
coals????), and then rising in the
annulus between the two cylinders,
and only when entering the area of
the main flame would those gases
combust. But this supposition of
FULL reversal of the air flow is
impossible because there are no
pyrolytic gases moving upward from
the MPF. <span
class="Apple-converted-space"> </span><o:p
class=""></o:p></span></div>
</div>
<div style="margin-bottom: 12pt;" class="">
<div style="margin: 0in 0in 0.0001pt;
font-size: 11pt; font-family: Calibri,
sans-serif; background-color: white;"
class=""><span style="font-size: 12pt;
font-family: Helvetica, sans-serif;"
class="">Conclusion: In a TLUD
stove, there can be PARTIAL downward
drafting of the created pyrolytic
gases when caused by natural draft
of secondary air to counteract the
flow of primary air. This is
educational, but what is possible is
not necessarily desirable or
practical. <span
class="Apple-converted-space"> </span><br
class="">
--<span
class="Apple-converted-space"> </span><br
class="">
Doc / Dr TLUD / Prof. Paul S.
Anderson, PhD<br class="">
Email: <span
class="Apple-converted-space"> </span><a
href="mailto:psanders@ilstu.edu"
target="_blank" style="color:
rgb(149, 79, 114);
text-decoration: underline;"
class="" moz-do-not-send="true">psanders@ilstu.edu</a><u
class=""><span style="color:
blue;" class=""> <span
class="Apple-converted-space"> </span></span></u>Skype:
paultlud Phone:<span
class="Apple-converted-space"> </span><span
class="MsoHyperlink" style="color:
blue; text-decoration: underline;">+1-309-452-7072</span><u
class=""><span style="color:
blue;" class=""> <span
class="Apple-converted-space"> </span></span></u>Website: <span
class="Apple-converted-space"> </span><a
href="http://www.drtlud.com/"
target="_blank" style="color:
rgb(149, 79, 114);
text-decoration: underline;"
class="" moz-do-not-send="true">www.drtlud.com</a><o:p
class=""></o:p></span></div>
</div>
<div class="">
<div class="">
<div class="">
<div style="margin-bottom: 12pt;"
class="">
<div style="margin: 0in 0in
0.0001pt; font-size: 11pt;
font-family: Calibri,
sans-serif; background-color:
white;" class=""><span
style="font-size: 12pt;
font-family: Helvetica,
sans-serif;" class=""><o:p
class=""> </o:p></span></div>
</div>
</div>
</div>
</div>
</div>
</div>
<p class="MsoNormal" style="margin: 0in 0in
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background-position: initial initial;
background-repeat: initial initial;"><span
style="font-size: 12pt; font-family:
Helvetica, sans-serif;" class=""><o:p
class=""> </o:p></span></p>
</div>
</div>
</div>
</div>
</div>
</blockquote>
<div style="margin: 0in 0in 0.0001pt; font-size: 11pt;
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font-family: Calibri, sans-serif;" class=""><span
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