[Default] On Tue, 13 Mar 2012 08:36:41 -0300,"Kevin" <[email protected]> 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 _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
