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<DIV><FONT size=2 face=Arial>Frans,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>It is exciting to have you bring up these
concerns. There is a question I have had for a long time, and
your contribution reminds me about it. It has to do with the
pressures within the stove. Perhaps you and the list can help answer this
question.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>First to address your concerns. There is a
sweet spot as to how much blockage the stove can manage. It lies between
to much, which blocks the flow and creates the attenuation you describe,
and to little so that the combustor doesn't work. I did not know that the
venturi created a back pressure, I assumed that the back pressure was created by
the obstruction of the tubes and fan. I found the sweet spot by emperical
experimentation. I now know that this balance includes back pressure from
the Venturi, if I understand you correctly. So the equation
now includes the resistance of three things: tubes, stationary fan
blade, and Venturi back pressure. I included your concern into the design
without my even knowing it. Its all a balance. Thank you for
your input, it is very good to help me understand more about the
stove. The combustor has been tested at Aprovecho and does work, so the
idea is good.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>The question I have had for so long is this:
When the wood gas emerges from the wood what is its pressure and how long does
it take for the wood gas to drop to near atmospheric pressure? When I
measured the pressure in a stove with a manometer which measured down
to 1/100th of an inch of water column, it measured at atmospheric pressure
throughout the stove. The water column did not move at all (I
understand from Crispin that I must measure down to 1/1000th of an inch to
find pressure differences). Since the water column did not move when
I measured the pressure at the pyrolytic front, that implies that the wood gas
either reaches atmospheric pressure quickly or comes out of the wood at near
atmospheric pressure. Whatever the case, the wood gas comes out of the
wood with enough force to push the atmosphere, which weighs twice as much
as the wood gas, out of the stove. That is a considerable amount of
force. I wonder how much pressure pyrolysis could build up in a
confined container? A lot I would guess, enough to cause an
explosion. Is the pressure of the emerging wood gas dependent on the
pressure of the gas it emerges into?</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Respectfully,</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Kirk</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<BLOCKQUOTE
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dir=ltr>
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=peetersfrans@telenet.be href="mailto:peetersfrans@telenet.be">Frans
Peeters</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=stoves@lists.bioenergylists.org
href="mailto:stoves@lists.bioenergylists.org">'Discussion of biomass cooking
stoves'</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, September 17, 2015 3:06
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Stoves] Strata combustor
general principles</DIV>
<DIV><FONT size=2 face=Arial></FONT><BR></DIV>
<DIV class=WordSection1>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt">Dear,Kirk<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US> You don’t see :it is not a
closed compressed system !<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US>But any reaction vessel (V1 ) with a venturi
attenuation at the output gives a back reaction in all
directions ,so flow attenuation under the grate air input
.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US>By over total power the air input BECOMES SMOKE OUTPUT TOO .! So
invers to your idea ;<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US>A V1 rocket has an input COMPRESSOR powered by the traveling
speed plus a constant fuel input so a nice VENTURY output
.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US>1and 2 you don’t have it in a stove of half info
.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US> Yours<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US>Rocket scientist<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Calibri','sans-serif'; COLOR: #1f497d; FONT-SIZE: 11pt"
lang=EN-US><o:p> </o:p></SPAN></P>
<DIV>
<DIV
style="BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; PADDING-BOTTOM: 0cm; PADDING-LEFT: 0cm; PADDING-RIGHT: 0cm; BORDER-TOP: #b5c4df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt">
<P class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; FONT-SIZE: 10pt"
lang=NL>Van:</SPAN></B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; FONT-SIZE: 10pt" lang=NL> Stoves
[mailto:stoves-bounces@lists.bioenergylists.org] <B>Namens
</B>kgharris<BR><B>Verzonden:</B> donderdag 17 september 2015
4:58<BR><B>Aan:</B> Discussion of biomass cooking stoves<BR><B>Onderwerp:</B>
Re: [Stoves] Strata combustor general
principles<o:p></o:p></SPAN></P></DIV></DIV>
<P class=MsoNormal><o:p> </o:p></P>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">Dr. Boll and
Crispin,</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">Thank you for your
well considered responses. I especially like the idea of balancing the
reactor fuel chamber volumn with the combustor size. I will keep this in
mind as I progress, and seek that balance. </SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">I don't quite
understand Crispins flame tube. The stove appears to be loaded
with charcoal, so there should not be any smoke. If the clay is
insulating clay than the tube would provide a hot environment for the CO to
burn, if there is a source of secondary air. If the
stove burns wood, by what principles does the tube work?
Is air injected inside the tube? This would make use of the Venturi
effect like Roberto's stove. The flame gasses accellerating into
the tube would drop in pressure and the pressure difference would help
the atmosphere push secondary air into the flame to equalize the pressure,
providing good mixing. This seems to me like it might work well if that
is how it works. Is there something else that I don't
see?</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">Kirk
</SPAN><o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal> <o:p></o:p></P></DIV>
<BLOCKQUOTE
style="BORDER-BOTTOM: medium none; BORDER-LEFT: black 1.5pt solid; PADDING-BOTTOM: 0cm; MARGIN: 5pt 0cm 5pt 3.75pt; PADDING-LEFT: 4pt; PADDING-RIGHT: 0cm; BORDER-TOP: medium none; BORDER-RIGHT: medium none; PADDING-TOP: 0cm">
<DIV>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">----- Original
Message ----- <o:p></o:p></SPAN></P></DIV>
<DIV>
<P style="BACKGROUND: #e4e4e4" class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">From:</SPAN></B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt"> <A
title=boll.bn@t-online.de href="mailto:boll.bn@t-online.de">Boll, Martin
Dr.</A> <o:p></o:p></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">To:</SPAN></B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt"> <A
title=stoves@lists.bioenergylists.org
href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</A>
<o:p></o:p></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">Sent:</SPAN></B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt"> Wednesday,
September 16, 2015 6:35 AM<o:p></o:p></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt">Subject:</SPAN></B><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; FONT-SIZE: 10pt"> Re: [Stoves]
Strata combustor general principles<o:p></o:p></SPAN></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<P class=MsoNormal>Kirk, <o:p></o:p></P>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal>first of all, your stoves and thoughts about TLUD's are
very interesting. And in my opinion<o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal> the venturi-concept, you are talking about, -how
ever managed- will be generally the next important step for better burning;
- and for less blacked pots!!! <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal>A presumption I made a year or two
ago: <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal>The (nominal-) power rate of a good working stove has a
more or less narrow relation to the grate-surface, and/or the
burning-chamber-volume.<o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal> I calculated the given numbers of some different
commercial stoves. My calculations confirmed my
guess.<o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal>I dont remember the numbers, but it is easy to calculate
the numbers out of available commercial data.<o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal>Additional I remind to Crispin's postings, some time
ago:<o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal>He reported, that he made the burning-chamber of some
coal stoves in Ulanbaator smaller, by just filling some space of the
burning-chamber-space with bricks. And some surface of the grate. In
combination with special incending-procedure, that gave better burning; even
by transforming the may of stoves there, there was an enormous reduction
(more than 90%) of air-pollution. <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal>So I suspect, if you would use the right-balanced amount
of burning-chamber-volume, you could get a step forward. The volume
within the venturi-riser-burner-tube should be included in the calculation;
but in the tube there will be, -hopefully- a burning some similar to a LPG
or NG flame, which will afford less volume. <o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal>You could take the power-rate which you achieve with low
emission, for extrapolating the stove dimensions for your desired 5 kW
output.<o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal>Regards<o:p></o:p></P></DIV>
<DIV>
<P class=MsoNormal><o:p> </o:p></P></DIV>
<DIV>
<P class=MsoNormal>Martin<o:p></o:p></P></DIV></BLOCKQUOTE></DIV>
<P>
<HR>
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