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<DIV><FONT face=Arial>Dear Paul</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=paul.olivier@esrla.com href="mailto:paul.olivier@esrla.com">Paul
Olivier</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> Wednesday, March 14, 2012 1:38
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Stoves] radiant heat
capture, total heat measurement</DIV>
<DIV><BR></DIV>
<DIV>Alex,<BR><BR>I took three sets of temperature readings with and without
the
dome.<BR><BR>
With Without<BR>Reading 1 - 500
C 563 C<BR>Reading 2 - 473 C 578
C<BR>Reading 3 - 470 C 571 C<BR><BR>All measurements
were taken at the same height above the burner.<BR>With the dome, the probe
remained its normal color.<BR>Without the dome, the probe got red
hot.<BR><BR>The burner that I am using is a Belonio burner.<BR>In a first step
I added a burner housing to the Belonio burner.<BR>In a second step I added
the dome.<BR>I can't imagine that the burner housing alone
accounts<BR> for the much better boiling time that I get in comparison to
Belonio.<BR>I am totally at loss in explaining these temperature
readings.</DIV>
<DIV> </DIV>
<DIV><FONT face=Arial># The above results seem consistent with the hypothesis
I presented in my posting of 13 March, 8:37 AM ADT. Basically: The Belonio
blue flame has low luminosity, while with the dome, it is heated by the non
luminous blue flame gases, and the "loss by radiadiation from the dome" cools
the gases. You seem to have missed the posting or it point. Accordingly, I
include a copy below.</FONT></DIV><FONT face=Arial></FONT></BLOCKQUOTE>
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<DIV><FONT face=Arial>Best wishes,</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Kevin</FONT></DIV>
<DIV><BR><BR>Paul<BR><BR><BR><FONT
face=Arial>*****************************************************************************</FONT></DIV>
<DIV>
<DIV> </DIV>
<DIV>----- Original Message -----
<DIV>From: "Kevin" <<A
href="mailto:kchisholm@ca.inter.net">kchisholm@ca.inter.net</A>></DIV>
<DIV>To: "Discussion of biomass cooking stoves" <<A
href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</A>></DIV>
<DIV>Sent: Tuesday, March 13, 2012 8:36 AM</DIV>
<DIV>Subject: Re: [Stoves] radiant heat capture, total heat
measurement</DIV></DIV>
<DIV><BR></DIV>> Dear Andrew<BR>> <BR>> I think your very last
comment is very important, and that its importance is <BR>> being
overlooked.<BR>> "Yes the glowing dome will radiate more power than the
blue flame."<BR>> <BR>> A "blue flame" has very poor flame radiation
characteristics. A yellow or <BR>> red flame has very superior flame
radiation characteristics. "Flame <BR>> Luminosity" basically equals better
radiation characteristics.<BR>> <BR>> One way to look at it is that
"Blue Flames are too smart by half." :-) There <BR>> is a gain in
completeness of combustion, and probably higher temperature for <BR>>
"products of combustion", and reduced sooting of pots, BUT there is a <BR>>
significant loss in luminosity, and heat transfer to the pot by radiation.
<BR>> The Mesh Dome, heated by direct convection of the "blue flame" then
is in a <BR>> position to add a "radiation contribution" to heat transfer
capability.<BR>> <BR>> It would be a very interesting experiment to take
a "flame temperature" of <BR>> Paul Oliver's system, with, and without the
dome. My guess is that the <BR>> "flame temperature" of the "Blue Flame",
and the gases leaving the dome <BR>> would be similar, and relatively low,
even though the actual thermocouple <BR>> measured temperature of the gases
would be high. In very simplistic terms <BR>> (for illustrative purposes
only)<BR>> 1: Blue Flame temperature by radiation measurement: 1000<BR>>
2: Gas temperature above dome
(radiation)
1000<BR>> 3: Thermometer temperature of both
gases
1500<BR>> 4: Flame Emissivity of 1: and
2:
.2<BR>> 5: Flame emissivity for luminous
flame:
.8<BR>> <BR>> Thus, if some of the pyrolysis gases were diverted away
from the "blue flame <BR>> conditions", and were allowed to increase the
flame luminosity, there could <BR>> potentially be an opportunity to "have
your cake and eat it." More <BR>> specifically, the addition of some
"luminous fractions" to the flame could, <BR>> for example increase flame
luminosity to say .6. but with a drop in actual <BR>> gas temperature to
say 1300 because of incompleteness of combustion.<BR>> <BR>> In other
words, "Heat Transfer capability to the Pot" would be:<BR>> 1: Blue flame:
1500 x .2 = 300<BR>> 2: Blue + Yellow" flame conditions = 1300 x .6 =
780<BR>> <BR>> For a "Blue Flame + Radiation Dome, conditions might
be<BR>> 1300 x .4 = 510<BR>> <BR>> (NOTE: All these numbers are
arbitrary and purely illustrative, to explain <BR>> the
concepts)<BR>> <BR>> So.... if the concepts are correct, then it would
seem that the best way to <BR>> make a stove would be to make one with a
burner that produced BOTH yellow <BR>> flame(for luminosity) and a blue
flame (for completeness of combustion).<BR>> <BR>> Does that "hang
together for you?<BR>> <BR>> Best wishes,<BR>> <BR>> Kevin<BR>>
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