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<FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'>HI Paul:<BR>
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I am not understanding what you want to say in your point 5 below. <BR>
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As far as I can see they did chimney D of 47, 63 and 100% of stove D.<BR>
They did concentrator D of like 17, 37, 70 and 100% stove D.<BR>
They note that concentrator D = 0.7 stove D generates same burn rate as 1.0D.<BR>
They note that a chimney D = 0.63 stove D (close to 0.7D) has a burn rate only 10% less than 1.0D.<BR>
Conclusion minor obstructions have little impact on burn rate, presumably allowing room to have a concentrator which can optimize emissions reduction, but I don’t think that optimum was tested.<BR>
Good work raising questions still to be answered!<BR>
<BR>
I haven’t seen where they extrapolated 0.63 to 0.7 or any data sets of 0.5 and 0.7D in either chimney or concentrator sizes, if that is what your point 5 is referring to. <BR>
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Its too bad they didn’t do a chimney height of 0.5D, but it seems the fire power would be down and emissions up, requiring either a higher chimney as they explored or a more efficient combustor as Kirk explored and found. <BR>
<BR>
If culture demands the short height, then Kirk-like combustor or fan forcing seems to be needed.<BR>
<BR>
Paul<BR>
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On 8/29/14, 11:26 AM, "Paul Anderson" <<a href="psanders@ilstu.edu">psanders@ilstu.edu</a>> wrote:<BR>
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Marc and all,<BR>
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I am glad that we have the Brizer et al paper. <BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'> <BR>
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Birzer, C; Medwell, P; Wilkey, J; West, T; Higgins, M; MacFarlane, G; Read, M. 2013. An analysis of combustion from a top-lit up-draft (TLUD) cookstove. Journal of Humanitarian Engineering, 2(1). <BR>
<BR>
<a href="http://www.ewb.org.au/jhe/index.php/jhe/article/view/11">http://www.ewb.org.au/jhe/index.php/jhe/article/view/11</a><BR>
<BR>
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</SPAN></FONT></BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'> It shows some serious testing. As a course project, these students did better measurements than so many other more-casual examinations of TLUD stoves. <BR>
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However, there are some differences between the academic and the practical aspects. I am making observations, not criticisms or compliments: [Also, if I have missed some point or incorrectly cited something, please excuse me for replying after only a quick re-reading.]<BR>
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1. The experimental TLUD was a single walled fuel canister. (not what is being made in TLUD projects, with double walls.)<BR>
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2. The diameter is 200 mm (D = 8 inches), which is also uncommonly large.<BR>
<BR>
3. The study of chimney heights were with chimneys equal to very close to D [8"] and 1.5 x D [12 inches] and 2 x D [16 inches]. Interesting results. But there are no TLUDs that use RISERS or Pre-pot chimneys greater than 0.5 x D. So the results are interesting, but are not related to the practical aspects of making TLUDs for household usage. <BR>
<BR>
4. A tall chimney can favorably impact the clean combustion of the gases even if there is no concentrator. The other extreme, being NO chimney, will be results of burning the gases at will at the top of an open fuel chamber, and that will be with poor emissions. Adding a concentrator with a short chimney has a chance to have better (lower) emissions. <BR>
<BR>
5. I question whether or not 0.63 x D should be rounded up to 0.7 or rounded down to 0.6. Just an observation. But the difference between 0.47 and 0.63 is not as noteworthy as between 0.5 and 0.7 when explaining the rather large difference in results between the two sets of data and comparing to the 1.0 data set that is similar to the 0.63 data set.<BR>
<BR>
I met these Australian researchers when they, while still students, attend the CHAB Camp conducted by myself and Hugh McLaughlin and Paul Taylor (in 2010). Great guys, eager learners, keen to run experiments, and they completed what they set out to do. I again say Congratulations. And Thank You.<BR>
<BR>
But they were doing just the start of what is needed, and what could be done in university courses, and by the rest of us. To over rely on their results and methods should not be the basis for advancing TLUD (or any other) technology. Replicate, alter, advance, and replicate again.<BR>
<BR>
Paul<BR>
<BR>
Doc / Dr TLUD / Prof. Paul S. Anderson, PhD <BR>
Email: <a href="psanders@ilstu.edu">psanders@ilstu.edu</a> <BR>
Skype: paultlud Phone: +1-309-452-7072<BR>
Website: www.drtlud.com <<a href="http://www.drtlud.com">http://www.drtlud.com</a>> <BR>
On 8/29/2014 11:51 AM, Marquitusus wrote:<BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'> <BR>
Dear Paul and others,<BR>
<BR>
Thanks for your comments.<BR>
<BR>
If you think the 0.7 diameter hole is not correct, what about the other conclusions of this paper? for example, it says that "the optimal chimney height is seen to be at 1,5D and a with of D" (D = diameter of the burning chamber)<BR>
<BR>
Marc<BR>
<BR>
<BR>
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<HR ALIGN=CENTER SIZE="3" WIDTH="100%">Date: Fri, 29 Aug 2014 10:00:21 +0800<BR>
From: <a href="crispinpigott@outlook.com">crispinpigott@outlook.com</a><BR>
To: <a href="stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a><BR>
Subject: Re: [Stoves] Trying new burner for TLUD's<BR>
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"Anyone knows any other works on this aspect"<BR>
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(circle of flame)<BR>
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Dear Paul<BR>
<BR>
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I think that is exactly what Gus was doing. We had a discussion about it a couple of months ago. <BR>
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Regards <BR>
<BR>
Crispin testing cooking stoves with short chimneys - will report...<BR>
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Dear Marc, Julien, and all Stovers,<BR>
<BR>
There has been some good discussion (and hands-on work) about the combustor on the TLUDs. Here are some miscellaneous comments. <BR>
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1. Marc wrote:<BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'>(the paper says that the hole of the concentrator ring should be 70% of combustion chamber diameter. In terms of area, it means about 50% combustion chamber area)<BR>
</SPAN></FONT></BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'> I think that is mis-stated. Most concentrators holes are about half of the diameter of the full ring (fuel chamber diameter). For 6 inch diameter fuel chambers, the size most used for holes is 3 inch diameter (plus or minus half inch is fine). That hole is only 25% of the area of the whole disk. Dean Still (at Stove Camp) said that his is with a 4" dia chamber has a 2" hole (if I remember correctly). <BR>
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2. Marc also wrote:<BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'>I never liked (for cooking purposes) the single-thick flame that comes out of the concentrator ring that use most of the TLUD's designs, because you get a narrow over-heated spot in the bottom of the cooking pot, and in a result of that, you don't get a good heat distribution in the pot.<BR>
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I made a new "diffuser" burner, which gives a circular flame area, instead of a single one.<BR>
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<a href="http://youtu.be/mhl6tt2A4T0">http://youtu.be/mhl6tt2A4T0</a><BR>
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<BR>
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Anyone knows any other works on this aspect?<BR>
<BR>
</SPAN></FONT></BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'> <BR>
The use of an annulus (ring) of gases for combustion (vs. the central flame of concentrators) was in the very first item ever written about what is now known as TLUD stoves. See:<BR>
<BR>
<a href="http://www.drtlud.com/wp-content/uploads/2013/12/woodgas-stove-reed-larson-1996.pdf">http://www.drtlud.com/wp-content/uploads/2013/12/woodgas-stove-reed-larson-1996.pdf</a><BR>
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And that stove has difficulties with maintaining flame around the entire annulus when the supply of gases is not high. What I think I have been reading by the recent researchers is to have something like a concentrator and then an annulus, ALL below the pot. I hope that can help solve the issues.<BR>
<BR>
Paul<BR>
<BR>
Doc / Dr TLUD / Prof. Paul S. Anderson, PhD <BR>
Email: <a href="psanders@ilstu.edu">psanders@ilstu.edu</a> <BR>
Skype: paultlud Phone: +1-309-452-7072<BR>
Website: www.drtlud.com <<a href="http://www.drtlud.com">http://www.drtlud.com</a>> <BR>
On 8/25/2014 2:04 AM, Marquitusus wrote:<BR>
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</SPAN></FONT><BLOCKQUOTE><FONT FACE="Calibri, Verdana, Helvetica, Arial"><SPAN STYLE='font-size:12pt'> <BR>
Hi Julien, <BR>
<BR>
<BR>
<BR>
Thank you for the info. and the paper.<BR>
<BR>
<BR>
<BR>
<BR>
Yesterday I was applying all this information to my new burner design. I realized that, according to this paper, the holes should be bigger if I wanted not to reduce the draft. I assumed my new burner act as the typical "concentrator ring", and make its empty area to be the same size as the paper recommends (the paper says that the hole of the concentrator ring should be 70% of combustion chamber diameter. In terms of area, it means about 50% combustion chamber area)<BR>
<BR>
<BR>
<BR>
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What I can say since now, regarding the firsts test with this new burner, is that apart from the distribution effect, it mantains the mixing effect (pyrogas+secondary air) of the classical concentrator ring. I have observed that the flames coming out of the secondary air entrance holes, tend to concentrate in the center of the burner, just in the bottom of the area wich is not open. Then they make a spin movement, and finally find its way through the empy areas.<BR>
<BR>
<BR>
<BR>
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I suppose this movements in the bottom part of the burner, very near the base of the flames, contribute to the mixing process. But, as you say, I haven't tried it under difficult conditions, so I cannot say it would be desirable in all conditions.<BR>
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<BR>
<BR>
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Following your thoughts, I also think we should have to find the optimal distance between the ring and the secondary air intake. In this sense, I think that it should be desirable to mantain this distance as short as possible, in order to not losing heat through the sides. If we put a long mixing/expanding tube (chimney), we will have a very large emitting heat area. If we find there is no alternative, then we'll have to think about insulating all this area. That is the reason why I try to mantain chimneys as short as possible. What do you think about it?<BR>
<BR>
<BR>
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All the best,<BR>
<BR>
Marc<BR>
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<HR ALIGN=CENTER SIZE="3" WIDTH="100%"> Date: Sun, 24 Aug 2014 09:56:59 -0400<BR>
From: <a href="winter.julien@gmail.com">winter.julien@gmail.com</a> <<a href="mailto:winter.julien@gmail.com">mailto:winter.julien@gmail.com</a>> <BR>
To: <a href="stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a> <<a href="mailto:stoves@lists.bioenergylists.org">mailto:stoves@lists.bioenergylists.org</a>> <BR>
Subject: [Stoves] Trying new burner for TLUD's<BR>
<BR>
<BR>
<BR>
Hi Marquitusus;<BR>
<BR>
<BR>
<BR>
<BR>
Your burner looks like an interesting idea. It is worth checking to see if it will operate under difficult conditions, such as low pyrogas production from fuel > 12% (wet wt.) moisture. <BR>
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<BR>
<BR>
<BR>
I have been testing various options such as annular rings for pyrogas, concentrator disks (not rings cf. Anderson and Wendelbo), and swirls. The problems with burners emerge with the fuel I described above. What I find is that (1) objects over the top of the TLUD reactor that prevent secondary air descending toward the fuel bed, and (2) swirls generated near the base of the gas flame, don't work well under difficult TLUD operating conditions. I am going to post the results of experiments on these shortly.<BR>
<BR>
<BR>
<BR>
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The conclusion I have reached (for the burners I have tested) is that it is best not to interfere too much with the bottom of the gas flame.<BR>
<BR>
<BR>
<BR>
<BR>
However, once the gas fame is well established, modifying it higher up in the burner to create turbulence or spread the flame could be a good idea. Therefore, I think your idea has merit. If you haven't already done so, you may want to experiment with the distance your disk is above the secondary air intake, i.e. is there sufficient space for the gas flame to expand.<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
Based on the work by <BR>
<BR>
<BR>
<BR>
<BR>
Birzer, C; Medwell, P; Wilkey, J; West, T; Higgins, M; MacFarlane, G; Read, M. 2013. An analysis of combustion from a top-lit up-draft (TLUD) cookstove. Journal of Humanitarian Engineering, 2(1). <BR>
<BR>
<a href="http://www.ewb.org.au/jhe/index.php/jhe/article/view/11">http://www.ewb.org.au/jhe/index.php/jhe/article/view/11</a><BR>
<BR>
<BR>
<BR>
<BR>
you should check to see that the size of your disk, relative to the burner outer diameter, doesn't slow down the TLUD reaction too much.<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
All the best,<BR>
<BR>
Julien.<BR>
<BR>
-- <BR>
<BR>
<BR>
Julien Winter<BR>
Cobourg, ON, CANADA<BR>
<BR>
<BR>
<BR>
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