Measuring accurate flame temperatures

["Thomas Reed" <tombreed@attbi.com>]

Dear Dan and All:

Dan often has the right questions and often the right answers. Since you
ask, Dan, the gas temperature can be measured  accurately using a "suction
thermocouple" or a "sodium line reversal" spectroscopic technique.

The bare thermocouple radiates powerfully at 1000 C and the hot gas at
1500-2000 C is moving very slowly over the tip, resulting in low heat
transfer to the TC and rapid heat loss.

To fix this, a close fitting tube lined with radiation shields is attached
around the thermocouple and attached to a vacuum source.  The radiation
shields reduce radiant heat loss from the thermocouple.  Gas is drawn over
the tip at high velocity, thus increasing the convective heat transfer.  A
plot of gas velocity vs indicated T should asymptote out at the correct gas
temperature.

I think this was first developed (1950?) by the National Bureau of Standards
(now NIST?).

Alternatively one can use "sodium line reversal" to measure accurate flame
temperature.  BUT NOT a bare TC.

Onward,      TOM REED        BEF
----- Original Message -----
From: <Carefreeland@aol.com>
To: <stoves@crest.org>; <gasification@crest.org>
Sent: Monday, March 11, 2002 4:36 PM
Subject: GAS-L: Re: Measuring temperature


> Dear Tom, Ron, Peter and all,
>        Some useful information here, I would like to know if a well would
> help the flowing gas readings for a thermocouple or is there a better way?
> This is critical to many measuring uses. A thermometer will not read
> accurately under the stars for the same reason. It only gives a reading
> indicative of surface temperatures due to radiative cooling.
>        I will be slipping mostly into lurker class for a while as my
business
> is really picking up. Thanks all for the interest on my budding website. I
> recorded 74 hits in the first week for my simple beginning webpage.  I
hope
> to develop this considerably more with time so stop by again. Thanks for
all
> of the support from listers in conclusion of my first year listing with
the
> BEF.  Hope 2002 is a brighter year for everyone.
>        If anyone has a specific question I can help with, I'll still make
> time as I can. I leave the floor open for new subjects and new voices.  To
> all you lurkers. No one will ever know just what you know, until it's
shared.
>  It my be more valuable shared than you think.  This from personal
> experience.
>        I had an electronics teacher who said that the only stupid question
> was one that was never asked. With all of this talent in one place that
> statement resounds.
>        Take care and I'll see you more in the next slow spell.
>                 Daniel Dimiduk
>
> -
> Gasification List Archives:
> http://www.crest.org/discussion/gasification/200202/
>
> Gasification List Moderator:
> Tom Reed, Biomass Energy Foundation,  Reedtb2@cs.com
> www.webpan.com/BEF
> List-Post: <mailto:gasification@crest.org>
> List-Help: <mailto:gasification-help@crest.org>
> List-Unsubscribe: <mailto:gasification-unsubscribe@crest.org>
> List-Subscribe: <mailto:gasification-subscribe@crest.org>
>
> Sponsor the Gasification List: http://www.crest.org/discuss3.html
> -
> Other Gasification Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>


-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/200202/
http://crest.org/discussiongroups/resources/stoves/ (Under construction)
http://www.ikweb.com/enuff/public_html/Stoves.html (Original)

Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com

List-Post: <mailto:stoves@crest.org>
List-Help: <mailto:stoves-help@crest.org>
List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
List-Subscribe: <mailto:stoves-subscribe@crest.org>

Sponsor the Stoves List: http://www.crest.org/discuss3.html
-
Other Biomass Stoves Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon

For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm