<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">Paul and list:</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I don’t think there is any conflict that traditional TLUDs do not experience down draft. But the Putnam experiments have been trying to explore what Nat Mulcahy has patented and been selling for about a decade. (I met Nat at the 2008 Biochar conference in Newcastle UK.)</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>This week’s list messages is the only negative dialog I remember since the 2009 ETHOS meeting where Nat explained his work. I wasn’t there, and I know some didn’t believe it going in, but I thought he had convinced everyone. Can we hear from others who were there? I am questioning the word “consensus” below.</div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I doubt that any of those with negative reactions to Nat’s work have had a chance to play with the Lucia’s. I have - for at least 3-4 hours in his lab in Italy - on maybe 3 different models both powered and natural draft. Anyone who has been saying that the Lucia is a TLUD had that experience? </div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I assert that Nat has not been fooling people, so here is a guarantee for a beer to anyone who can prove via a test that either the Lucia or the new work is simply another TLUD. I assert it is should be easy with simple tests to prove that Nat <b class=""><u class="">IS</u></b> exploiting the Bernoulli principal. My Googling has shown there are plenty of practical applications of one airflow to create a low pressure area in another area. </div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I’ll keep working on this. I need help with the mathematics of the Bernoulli equation for some specific stove geometry. I’m looking for an ME who has been teaching the Bernoulli equation in the classroom (and better a lab).</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I have never seen a plot of pressure in the TLUD design that made sense. Anyone able to send me one that is backed up by an experiment? Temperature, charcoal amounts, pyrolysis gases, and power levels are easy. Not looking for these. Pressure differences are tiny. There might be some ways to measure velocities and densities, but haven’t seen those either. All these needed for the Bernoulli equation.</div><div class=""><br class=""></div><div class="">Ron</div><div class=""><br class=""></div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On Mar 24, 2018, at 4:18 PM, Paul Anderson <<a href="mailto:psanders@ilstu.edu" class="">psanders@ilstu.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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Alex and all,<br class="">
<br class="">
Thank you all for your comments. There was some discussion about
this "downdraft in updraft" a few years ago, with a consensus of no
downdraft occuring. It is only because of the Heath Putnam videos
that the topic has returned. <br class="">
<br class="">
The discussion these last few days has been interesting. Some
comments / hypotheses have been given. Some suggestions of how
additonal tests could be run have been made. But nobody has
replicated the Putnam experiments or tried some new test. I hope
that this will eventually be done, recorded on video, and posted for
all of us to see. <br class="">
<br class="">
Until then, that little bit of doubt still lingers. Something
scientific has not yet been fully tested. This IS the frontier of
cookstove technology.<br class="">
<br class="">
This topic supports my contention that there is still much to learn
about TLUD technology and micro-gasification in general. TLUD
stoves and micro-gasifiers will contnue to get better as the world
eventually recognizes that they are burning gases (made inside the
devices), not directly burning solid fuels. And they are not like
the old "stick burners" that keep hanging around and are promoted to
impoverished people although stick burners and charcoal burners will
never resolve the world's cookstove problems.<br class="">
<br class="">
Paul<br class="">
<br class="">
<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 12:11 PM, alex english
wrote:<br class="">
</div>
<blockquote type="cite" cite="mid:CA+6hwOpp7vk3sDP6GAVPDi2=oE2B4_B=3NxJpVwqDTLh93fWBw@mail.gmail.com" class="">
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<div class="">Paul,</div>
<div class="">Lacking anything like data backed proof of down-drafting
in these little stoves without fans. I say no way.</div>
<div class=""><br class="">
</div>
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.
<div class=""><br class="">
</div>
<div class="">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. </div>
<div class=""><br class="">
</div>
<div class="">There's no pressure gradient to drive this fantasy in the
real world.</div>
<div class=""><br class="">
</div>
<div class="">Ah there's Hugh now....driving his own spike.</div>
<div class=""><br class="">
</div>
<div class="">Done</div>
<div class=""><br class="">
</div>
<div class="">Alex</div>
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