Matthew,<br><br>I wanted to compare how long it would take to bring water to a boil using the same pan without a lid:<br> one test using the 150 gasifier and the other test using a the propane stove in my kitchen.<br>The propane stove in my kitchen represents an ideal premix burner.<br>
<br>Ron Larson asked precisely the same thing: that I try to boil water without the dome.<br>I feel strongly the boiling time will at least double.<br>Convective heat transfer is so inefficient (as I demonstrated with my propane burner),<br>
and since my burner is not a premix burner, <br> the transfer of heat will far worse than my propane burner.<br><br>The big problem with a diffusion flame, as you well know,<br> is that the pot has to be situated at the end of the diffusion tail.<br>
If the pot is placed too close to the flame, the flame flares out and only hits the edges of the bottom of the pot.<br>Things are quite different with the dome.<br><br>The dome rises about two inches above the gas burner, and the flame does not flare out underneath the dome.<br>
It does precisely the opposite: the diffusion tail comes to a single point right at the apex of the dome.<br>Wind barely has an influence on what happens within the dome,<br> although the dome does draw in some secondary air.<br>
This means that the height of the dome above the burner holes is not a major issue.<br><br>Also a dome-shaped emitter has more surface area than a flat emitter of the same diameter.<br><br>Thanks.<br>Paul<br><br><div class="gmail_quote">
On Sun, Mar 11, 2012 at 4:48 AM, Matthew Redmond <span dir="ltr"><<a href="mailto:mredmond3@gatech.edu">mredmond3@gatech.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Paul,<div><br></div><div>I looked into ray tracing more to see if I have access to the necessary software. I have access to some, and some is open source, but either one would take too much time to learn right now. As the stove is (without the reflective aluminum foil) view factor analysis is probably plenty and ray tracing is overkill anyway. </div>
<div>
<br></div><div>One question: as you stated in the biostoves list, you used a propane stove in your kitchen for the ~ 6 min boil test, but your gasifier for the ~ 3 min burn test. Why the switch? Could you try running the gasifier without the screen and see how long it takes for water to boil? I'm sure the biostoves list would be interested in this as well.</div>
<div><br></div><div>Regards,</div><div>Matt</div><div class="HOEnZb"><div class="h5"><div><br><br><div class="gmail_quote">On Wed, Mar 7, 2012 at 3:33 PM, Paul Olivier <span dir="ltr"><<a href="mailto:paul.olivier@esrla.com" target="_blank">paul.olivier@esrla.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Matthew,<br><br>See comments.<br><br><div class="gmail_quote"><div>On Wed, Mar 7, 2012 at 7:52 PM, Matthew Redmond <span dir="ltr"><<a href="mailto:mredmond3@gatech.edu" target="_blank">mredmond3@gatech.edu</a>></span> wrote:<br>
</div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Paul,<div><br></div><div><div>Good luck with the experiment. </div></div></blockquote><div><br>I did not have time yesterday to do the experiment with the aluminum foil.<br> </div><div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>Though view factor can give you a good approximation, only ray tracing can give you a really accurate solution for radiation reflection, etc. This requires complex and expensive software.</div></blockquote></div><div>
<br>I do not know what ray tracing is. <br>
<br></div><div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div><br></div><div>If all goes well with the experiment and the aluminum reflection produces good results, I could try to find a numerical estimate using ray tracing for you and see how it matches the experiment. </div>
</blockquote></div><div><br>I would appreciate you help with this.<br>I think that two means of reflection are needed here.<br>The first would receive the laterally emitted thermal radiation and reflect it back to the pot.<br>
The second would receive the downwardly reflected thermal radiation and reflect it back to the pot.<br>
<br>To give you a better idea of how the burner assembly is constructed, take a look at the following jpegs.<br>Here you see the burner and burner housing:<br><a href="http://dl.dropbox.com/u/22013094/150%20Gasifier/Jpegs/013.jpg" target="_blank">http://dl.dropbox.com/u/22013094/150%20Gasifier/Jpegs/013.jpg</a><br>
Here you see the wire mesh dome that it is placed on top:<br><a href="http://dl.dropbox.com/u/22013094/150%20Gasifier/Jpegs/012.jpg" target="_blank">http://dl.dropbox.com/u/22013094/150%20Gasifier/Jpegs/012.jpg</a><br>Here you see a close-up of the two:<br>
<a href="http://dl.dropbox.com/u/22013094/150%20Gasifier/Jpegs/006.jpg" target="_blank">http://dl.dropbox.com/u/22013094/150%20Gasifier/Jpegs/006.jpg</a><br><br>For the laterally emitted radiation, we need an angled funnel that would surround the dome.<br>
For the downwardly emitted radiation, we need a slightly concave plate that would sit on top of the burner.<br> </div><div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>This will have to wait though as I am very busy right now with my studies.</div>
<div><br></div><div>By the way, I see you are based in Vietnam. Do you know Marc Pare there? Marc was a classmate of mine a few years back at Georgia Tech.</div></blockquote></div><div><br>I had invited Marc to come to Vietnam.<br>
I paid his hotel each month along with most of his basic expenses.<br>He ate lunch each day at my house.<br>Then one fine day he decided to start working with several key contacts of mine and left.<br>This was a strange experience.<br>
<br>Thanks.<span><font color="#888888"><br>Paul<br> </font></span></div><div><div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div><br></div><div>Regards,</div><div>Matthew</div><div>
<div><div><br>
<div class="gmail_quote">On Tue, Mar 6, 2012 at 3:40 PM, Paul Olivier <span dir="ltr"><<a href="mailto:paul.olivier@esrla.com" target="_blank">paul.olivier@esrla.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Matthew,<br><br>Yes, I will try today ordinary aluminum foil from my kitchen.<br>It will be raised a few mm's off the bottom of the burner.<br><br>Paul<div><div></div><div><br><br><div class="gmail_quote">On Wed, Mar 7, 2012 at 3:09 AM, Matthew Redmond <span dir="ltr"><<a href="mailto:mredmond3@gatech.edu" target="_blank">mredmond3@gatech.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span style="font-size:13px;font-family:arial,sans-serif">Paul,</span><div><span style="font-size:13px;font-family:arial,sans-serif"><br>
</span></div><div>
<span style="font-size:13px;font-family:arial,sans-serif">In response to your post on using tin foil (is this the same as aluminum foil?) to reflect radiation from the wire mesh back up to the pot, it should make a difference for the better. How much of a difference is more complicated. If you interested in calculating it, you should consider looking up some information on "View Factor Algebra." This will help you approximate the difference.</span></div>
<div><span style="font-size:13px;font-family:arial,sans-serif"><br></span></div><div><span style="font-size:13px;font-family:arial,sans-serif">-Matthew</span><span style="font-size:13px;font-family:arial,sans-serif"> </span></div>
<div><span style="font-size:13px;font-family:arial,sans-serif"><br></span></div><div><span style="font-size:13px;font-family:arial,sans-serif"><br></span></div>
<div><span style="font-size:13px;font-family:arial,sans-serif">Message: 8</span><br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">Date: Tue, 6 Mar 2012 16:45:14 +0700</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">From: Paul Olivier <</span><a href="mailto:paul.olivier@esrla.com" style="color:rgb(0,0,204);font-size:13px;font-family:arial,sans-serif" target="_blank">paul.olivier@esrla.com</a><span style="font-size:13px;font-family:arial,sans-serif">></span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">To: Discussion of biomass cooking stoves</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif"> <</span><a href="mailto:stoves@lists.bioenergylists.org" style="color:rgb(0,0,204);font-size:13px;font-family:arial,sans-serif" target="_blank">stoves@lists.bioenergylists.org</a><span style="font-size:13px;font-family:arial,sans-serif">></span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">Subject: Re: [Stoves] the 150 gasifier in operation in Vietnam</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">Message-ID:</span><br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif"> <CAOreFvbEXLfdF=</span><a href="mailto:HZPkg3-EOh5yZ_WUeD0DFqgn0e9JaYfees1Q@mail.gmail.com" style="color:rgb(0,0,204);font-size:13px;font-family:arial,sans-serif" target="_blank">HZPkg3-EOh5yZ_WUeD0DFqgn0e9JaYfees1Q@mail.gmail.com</a><span style="font-size:13px;font-family:arial,sans-serif">></span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">Content-Type: text/plain; charset="iso-8859-1"</span><br style="font-size:13px;font-family:arial,sans-serif">
<br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">Crispin,</span><br style="font-size:13px;font-family:arial,sans-serif">
<br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">You've seen the video of the dome that is red hot.</span><br style="font-size:13px;font-family:arial,sans-serif">
<a href="http://www.youtube.com/watch?v=80REBVTwpMo" style="color:rgb(0,0,204);font-size:13px;font-family:arial,sans-serif" target="_blank">http://www.youtube.com/watch?v=80REBVTwpMo</a><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">The dome emits radiant energy in all directions.</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">I placed a shield on the sides of the dome to stop the lateral loss of</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">radiant energy.</span><br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">You can see the shield clearly in the video.</span><br style="font-size:13px;font-family:arial,sans-serif">
<br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">But there is a lot of radiant energy (perhaps half) that goes down to</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">burner and does not heat the pot.</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">I want to put a piece of tin foil about 4 mm above the burner.</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">If it does not touch the burner, it should be more reflective.</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">The idea is to reflect radiant energy back up in the direction of the pot.</span><br style="font-size:13px;font-family:arial,sans-serif">
<span style="font-size:13px;font-family:arial,sans-serif">Does this make sense?</span><br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">What difference should this make?</span><br style="font-size:13px;font-family:arial,sans-serif">
<br style="font-size:13px;font-family:arial,sans-serif"><span style="font-size:13px;font-family:arial,sans-serif">Paul</span>
</div>
</blockquote></div><br><br clear="all"><br></div></div><font color="#888888">-- <br>Paul A. Olivier PhD<br>27C Pham Hong Thai Street<br>Dalat<br>Vietnam<br><br>Louisiana telephone: <a href="tel:1-337-447-4124" value="+13374474124" target="_blank">1-337-447-4124</a> (rings Vietnam)<br>
Mobile: 090-694-1573 (in Vietnam)<br>Skype address: Xpolivier<br>
<a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a><br>
</font></blockquote></div><br></div>
</div></div></blockquote></div></div></div><div><div><br><br clear="all"><br>-- <br>Paul A. Olivier PhD<br>27C Pham Hong Thai Street<br>Dalat<br>Vietnam<br><br>Louisiana telephone: <a href="tel:1-337-447-4124" value="+13374474124" target="_blank">1-337-447-4124</a> (rings Vietnam)<br>
Mobile: 090-694-1573 (in Vietnam)<br>
Skype address: Xpolivier<br><a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a><br>
</div></div></blockquote></div><br></div>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>Paul A. Olivier PhD<br>27C Pham Hong Thai Street<br>Dalat<br>Vietnam<br><br>Louisiana telephone: 1-337-447-4124 (rings Vietnam)<br>Mobile: 090-694-1573 (in Vietnam)<br>
Skype address: Xpolivier<br><a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a><br>