[Stoves] Down with Fantasy-draft stoves

Mon Jun 18 06:24:49 CDT 2018

Kirk,
This is an easy set up for freezing the MPF. Just add water. It produced
mostly char just like most TLUDs . It is not an open fire because when I
pull out the strainer, into the open, it immediately looses flame. Yes
there is some char combustion around the edges, just enough to add a pilot
to flame stability. There is a spectrum from ideological and scientific
purity to
technical and cost simplicity. I like to play at the extremes:)

Alex

On Mon, Jun 18, 2018 at 1:18 AM, Kirk H. <gkharris316 at comcast.net> wrote:

> Alex,
>
>
>
> This is a pot with some kind of open-burning stove inside it.  The air is
> entering the pot at the top but can enter the stove at the bottom or
> sides.  I question if this stove is a TLUD.   If it has a MPF and the
> gasses are being burned separately in a secondary flame with air supplied
> by the side holes, than it may be operating as a TLUD.  There are no gas
> flames at the top of the stove where the wood gas would mix with air coming
> over the top, as a TLUD would usually operate.  The flames are burning
> before they exit the chamber so my guess is that it is an open fire.
>
>
>
> I did some experiments on turn-down several years ago, directing some air
> downward in the reactor chamber.  It turned inward when it reached the top
> of the char and burned the wood gas as it rose out of the char, giving
> excellent turn-down.  I did not see it penetrate below the surface of the
> char let alone the MPF.  Also as the char level dropped during the burn,
> the air had to travel further downward to reach the surface.  It was heated
> by the fire as it descended and became buoyant, turning inward before
> reaching the char, so the flame was separate above the char.  It did still
> worked for turn-down.  Hypothetical primary air entering from above would
> probably do the same, heat as it descended, become buoyant, and not reach
> the top of the char.
>
>
>
> Kirk H.
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
> Windows 10
>
>
>
> *From: *alex english <aenglish444 at gmail.com>
> *Sent: *Sunday, June 17, 2018 2:24 PM
> *To: *Discussion of biomass cooking stoves
> <stoves at lists.bioenergylists.org>
> *Subject: *Re: [Stoves] Down with Fantasy-draft stoves
>
>
>
> Hi Stovies,
>
>
>
> This relates to Paul's doubts that all the air can come in the top of a
> TLUD.
>
>
>
> I took two off the shelf items and with no alterations and made a
> serviceable stove for wood pellet fuel . I placed a stainless holey cutlery
> strainer on a shim in the bottom of a small stainless milk pail. The
> strainer is 4 5/8 inches in diameter and 5 inches tall. The top was about
> 3/4 of an inch below the top of the pail. Half filled with pellets, which
> leaves the pellets 3.5 inches the below the pot.  Top lit, it burned for
> about 45 minutes with all the air coming in from the top. The migrating
> front headed 'south' predictably. A little ash formed around the edges.
> Good flame stability.
>
>
>
> It is basically a one speed device unless you manipulate the fuel profile.
>
> The pot position, size and shape is a factor as the exhaust and air pass
> by each other in close proximity going in opposite directions.
>
>
>
> A pretty simple stove.
>
>
>
> Alex
>
>
>
>
>
> On Thu, Mar 29, 2018 at 8:39 AM, Paul Anderson <psanders at ilstu.edu> wrote:
>
> Alex (and others)
>
> You wrote:
>
> That primary air  can be introduced above the fuel with the secondary air
> and drop down and spread out below the
> pyrolysis front.
>
>   I would certainly like to see this demonstrated (visible) or supported
> by scientific measurements.  Frankly, I have my doubts, especially if it is
> less than 20 cm (8 inches) in diameter..
>
> Paul
>
> Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD
> Email:  psanders at ilstu.edu
> Skype:   paultlud    Phone: +1-309-452-7072
> Website:  www.drtlud.com
>
> On 3/29/2018 5:40 AM, Andrew Heggie wrote:
>
> On 29 March 2018 at 01:32, alex english <aenglish444 at gmail.com> wrote:
>
> Andrew,
> If you are curious you can 'freeze' theTLUD process at any point by setting
> the a TLUD in a pan of water that shuts off the air and wicks water into
> the
> raw pellets in the bottom of the fuel chamber. They will swell and wick all
> the way up to the Migrating Pyrolysis Front . The Torrefied layer and the
> char above will not swell. A careful excavation of the fuel will reveal
> all.
> When I did  this with the 18 inch diameter chamber I found a horizontal
> layer of an inch, or a bit  less, of pellets in transition from raw pellet
> to torrified pellet to charred pellet.
>
> Thanks again Alex it's an interesting experiment but I'm quite happy
> to take your word for the horizontal MPF.
>
>
>
>    Misting the outside of the stove
>
> will can also give clear impression of a planar descent of the  MPF.
>
> I never did much with pellets as I felt they were not a likely fuel
> compared with stickwood and so not representative of most users  In UK
> I find them too expensive compared with other fuels.
>
> With very dry fuel like wood  pellet very little primary air is required.
> That primary air  can be introduced above the fuel with the secondary air
> and drop down and spread out below the
> pyrolysis front.  If introduced tangentially the cooler fresh air
> centrifuges to the outside edge of a round chamber and the flame tornados
> up
> the middle. A layer of fresh air one millimeter thick descending around the
> edge of a fuel chamber would be enough. Not a lot of control but this
> resembles what many people have used this sort in other contexts. With
> fussy fuel quality and placement it behaves in the steady top down way that
> a TLUD does with a little extra char burning.
>
> Yes I made many such vortex burners in my experiments, the largest
> being 4foot diameter but I supplied all the air from above and
> inevitably to excess.
>
>
> Andrew
>
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