[Stoves] radiant heat capture, total heat measurement

[Anand Karve]

Dear Stovers,
being a biologist, I am totally ignorant of the physics involved in this
discussion. 2 thoughts however came to my mind. Would the efficiency of a
TLUD or Rocket improve by fixing a wire gauze dome over the flame? Can a
flat piece of wire gauze work or does it have to be a dome?
Yours
A.D.Karve

On Thu, Mar 15, 2012 at 5:46 AM, <ajheggie at gmail.com> wrote:

> [Default] On Tue, 13 Mar 2012 08:36:41 -0300,"Kevin"
> <kchisholm at ca.inter.net> wrote:
>
> >
> >One way to look at it is that "Blue Flames are too smart by half." :-)
> There
> >is a gain in completeness of combustion, and probably higher temperature
> for
> >"products of combustion", and reduced sooting of pots, BUT there is a
> >significant loss in luminosity, and heat transfer to the pot by radiation.
> >The Mesh Dome, heated by direct convection of the "blue flame" then is in
> a
> >position to add a "radiation contribution" to heat transfer capability.
>
> Yes
> >
> >It would be a very interesting experiment to take a "flame temperature" of
> >Paul Oliver's system, with, and without the dome. My guess is that the
> >"flame temperature" of the "Blue Flame", and the gases leaving the dome
> >would be similar, and relatively low, even though the actual thermocouple
> >measured temperature of the gases would be high. In very simplistic terms
> >(for illustrative purposes only)
> >1: Blue Flame temperature by radiation measurement: 1000
> >2: Gas temperature above dome (radiation)                1000
> >3: Thermometer temperature of both gases                 1500
> >4: Flame Emissivity of 1: and 2:                                    .2
> >5: Flame emissivity for luminous flame:                         .8
>
> it looks like Paul has done thios now
> >
> >Thus, if some of the pyrolysis gases were diverted away from the "blue
> flame
> >conditions", and were allowed to increase the flame luminosity, there
> could
> >potentially be an opportunity to "have your cake and eat it." More
> >specifically, the addition of some "luminous fractions" to the flame
> could,
> >for example increase flame luminosity to say .6. but with a drop in actual
> >gas temperature to say 1300 because of incompleteness of combustion.
>
> The trouble is that could increase PICs leaving the flame unburnt.
>
> >So.... if the concepts are correct, then it would seem that the best way
> to
> >make a stove would be to make one with a burner that produced BOTH yellow
> >flame(for luminosity) and a blue flame (for completeness of combustion).
>
> Having got a good, short, premixed flame I wouldn't advocate going
> back to a diffusion flame.
>
> There is an example from the past where a chamical was added to town
> gas to make a yeallow flame, I think it was called carburetted gas,
> and a sall amount of petrol vapour was added to the CO+H2 mixture but
> this was before gas manteles were available. I think gas mantles t=do
> a better job as the light radiator because of the excitation
> characteristics of thorium being better than glowing sooty particles.
>
> AJH
>
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>


-- 
***
Dr. A.D. Karve
Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)
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