[Stoves] Wendlelbo's : Re Large TLUD --- TLUD Stove history

[Paul S. Anderson]

Andrew and all,   see below:

Quoting ajheggie at gmail.com:

> On Sunday 28 August 2011 14:49:48 Paul S. Anderson wrote:
>> (It took me four years 2001 to 2005 to get to that point of having  
>> concentrator lids on the TLUDs.
>
> Even the Reed-Larson stove diagrams from 1995ish showed a concentrator,
> essentially to disrupt flow and increase turbulence but it used the
> term "bluff body", this is to induce mixing in the eddies downstream. In
> that case it lead to a circle of flame around the edge of the stove,
> mimicking a flame from a pre mixed gas appliance.

The famous Reed-Larson device __spread__ the gases into an narrow  
annulus, which some might call "concentration while separating".  That  
annulus was its only serious defect because it did not have sufficient  
gases together to sustain a vigorous flame.

Wendelbo in the 1990s and Anderson in 2005 brought together the gases  
into a central hole, which seems a more appropriate use of  
"concentration while bringing together."

Whatever the name, Reed and Larson missed it and Wendelbo and Anderson  
got it right.

The rest of your message (below) gives an excellent description of why  
bottom-lit fires are more smokey and harder to control.  If we could  
now get more people to read and understand that message (which is the  
same from the "early days" or from "present day writings"), we will  
eventually get the IDD / TLUD technology into the minds of the the  
Stovers and eventually to the people who use the stoves.

Paul
-- 
Paul S. Anderson, PhD
Known to some as:  Dr. TLUD    Doc    Professor
Phone (USA): 309-452-7072   SKYPE: paultlud   Email: psanders at ilstu.edu
www.gtz.de/de/dokumente/giz2011-en-micro-gasification.pdf   (Best ref.)


>
>  Anderson wrote:
>> Those stoves only got that TLUD name  
>> in 2005, and were first named "Top-Lit UpDraft" in 2004 in the  
>> Anderson-Reed document at the LAMNET conference - found at the Stoves  
>> website).  From 1985 to 2005 Reed called the technology IDD, for    
>> Inverted DownDraft.)

> Heggie wrote:
> If one considers the strict interpretation of the terms then the IDD
> gasifier is more correct, it implies air control, Top Lit UpDraught can
> be applied to any fire that is toplit and then develops as an updraught
> fire and indeed in the early days of this list its use was explained by a
> person involved with masonry stoves in US domestic buildings. The reasons
> behind it are simple, if one lights a heap of biomass at the bottom the
> small amount of heat initially allows a low temperature burn of the char
> initially formed, most of the fire smoulders and heats the layers above
> to dry then pyrolise them. As things get hotter a flaming region under
> the fuel develops but the offgas is diluted by combustion products, water
> vapour and is quenched by the fuel it is heating up. The fuel:air mix is
> wrong to allow the flame to propagate. Freshly formed char will ignite at
> low temperatures but gases need a flame or to be above their autoignition
> temperatures to burn. Hence lots of smoke until a flame establishes at
> the top. If the fire is top lit all the combustion products are exposed
> to fresh air and a flame as an ignition source without having to pass
> through a mass of cold fuel wood. The only restraints on air supply are
> the natural air movements.
>
> This differs from the gasifier or pyrolyser concept which inherently
> control the air supply to restrict combustion to that necessary to gasify
> ( about 1/6 stoichiometric air for combustion) or pyrolyse ( less still)
> the biomass. Even The initial demo Tom Reed talks of has the shielding of
> the cigarette paper restricting air to that blown from below.
>
> AJH
>
>
>
>
>
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