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Post by satamax on Sept 7, 2018 0:49:57 GMT -8
I made a few changes today to try and check what has made improvements in the stoves performance. I may have stumbled on something new. I haven’t read of anything like it the forums before (the last part of this) So first with only the extra course in the riser- height 580mm, top gap 200mm. Burned well over all, when fuel was loaded it smoked for about 5 minutes then was quite clean. Could see a small amount of smoke/vapor through the main part of the burn. Next I added only the top bluff body (split brick)which is sitting on the final ledge or shelf in the riser. This protruded into the riser roughly 60mm. The burn was very similar to the previous one, very little visible smoke or vapor after the first 5 min. Lastly, I removed the small brick from in the riser and placed two bricks on top of the riser with an opening of 65mm by 250mm. Slightly larger than CSA of the system but smaller than the chimney. The top gap became 140mm. This was just to try it since it’s easy to access and change. It turned out that it seemed to be the best of all I’ve tried so far. It hardly smoked with new fuel and after the first part of the burn I couldn’t see anything coming from the chimney. I even climbed up to smell the exhaust from the roof and it had very little smell, maybe wet socks or wet charcoal. When I looked in the riser the base was all glowing orange and some of the p channel was glowing as well. Is this a too good to be true kind of thing? I can’t test with a Testo but it seemed to be the cleanest burn. Or is it bad because it will possibly be too much heat stress on the materials? I don’t have experience over the long term with this so any advice is welcome. I made a few changes today to try and check what has made improvements in the stoves performance. I may have stumbled on something new. I haven’t read of anything like it the forums before. Hi Travis, I'm convinced you've stumbled on something new. I tried this at home, built out of ceramic fibre board. It's a 120 mm system in two barrels, straight riser behind the firebox and above that widening to 200 mm. With a lid on it, reducing the outlet of the riser to 120x120 mm again. Height of the trumpet expansion part is just 210 mm with a lid on it of 50 mm thickness. In short: it works and yields remarkable results. I tried it as an open system without a door, with and without secondary air by means of a floor channel. Latest test as of today: riser end reduced to 113 cm², being smaller than the square riser but the same as 120 mm round. Floor channel mounted and also a threshold of 60 mm to damp down the racing of the burn somewhat. Results of two measured runs are quite positive. The thing is very, very powerful, burns remarkably clean. I will start a new thread about this, next addition could be a door of some sort. Well, if i may, if i understood correctly, Travis, you made a sort of narrowing at the top of the riser, via two bricks? Peter, when you first tried the DSR, i think you refered to the flames as a fountain of fire. I have asked before, about ceiling of the firebox ports. And at some point drawn two iterations with a square port entering the riser above, and the same with a round port. I think there is a way to make a "nuclear mushroom" burn in the riser, that way. I think the port needs to be bigger, than on the video but still have a fair bit of depression on the back side. A round hole, entering a vertical or horizontal riser, riser being perpendicular to the port's plate. And then you have the same behavior as in the video above, but on 360° And Travis, i think with your two bricks, you're adding a level of turbulence similar. Tho, in my idea, it would be better if it happened earlier in the burn. There's Shilo's and Matt's experiments with dual ports in different chambers. Also the latest by Hof, i'm sure i forget one or two others. These seem to work quite well. my opinion, is, make a normal batch, and right above the firebox, make a flat doughnut before the flames enter the heat riser, may be protruding 2 or 3 cm. into the riser, to create a second turbulence. Anybody sees what i'm on about? |
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Post by satamax on Sept 7, 2018 0:56:14 GMT -8
I couldn't follow what Travis had done when I last read this thread, but seeing this picture makes it clear to me now: www.dropbox.com/sh/v8pwo2oiaoa4p1r/AADNtSFouG-4XEwq7ZsuPWFUa?dl=0&preview=20180527_183207.jpgI found the same kind of thing with my experiments this summer, a chamber after a port followed by another larger port, slows down the gasses and allows them to mix and burn in a super hot environment. Adding a bit more Time for the Temperature and Turbulence to do their work. Well done, Travis  There might be something else than time and turbulence, pressure. We all agree, the pressure is higher before the port, than after, in the heat riser? Which in turn "races" the gases in the riser. In this case, adding a restriction on top of the riser, adds back a little pressure in the riser, where the gases might not race as much, so there is more time for these to burn. |
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Post by Vortex on Sept 7, 2018 6:21:37 GMT -8
Agreed, that second larger port creates a restriction that slows down the gases, increasing the pressure, allowing them more time to mix and burn. Normally you'd think slowing them down would create less turbulence, but the 1st port is squirting them in at high velocity, forcing them into a tight spin which in a confined super hot environment keeps them mixing. Perfect 3 T's.
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Post by satamax on Sept 7, 2018 7:54:06 GMT -8
I really have to test that ring or doughnut entering the riser.
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Post by Vortex on Sept 7, 2018 12:22:43 GMT -8
I think a circular hole of the same proportions as the second port would work just as well on Travis' setup, but I don't think it'll work if you try and do it on just a straight 6 inch round riser. Look at the short video he posted and you can see the riser is round at the bottom behind the port but then transitions into a larger square or rectangle, and then larger again as it goes up. I think it needs enough room between the 2 ports to expand and mix without too high a velocity. Nice. Yup like a second port. Yeah I was surprised by this because I haven’t seen such a bright orange in anything I’ve built before. But that’s only a few stoves. When I found the optimum size on the second port the hole riser/chamber seem to fluoresce like a neon tube glowing orange. |
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Post by Orange on Sept 10, 2018 6:41:54 GMT -8
Agreed, that second larger port creates a restriction that slows down the gases, increasing the pressure, allowing them more time to mix and burn. Normally you'd think slowing them down would create less turbulence, but the 1st port is squirting them in at high velocity, forcing them into a tight spin which in a confined super hot environment keeps them mixing. Perfect 3 T's. such a simple idea And the hot gasses go up creating a draft. |
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Post by travis on Sept 11, 2018 22:12:52 GMT -8
Wow, thanks Peter thats exciting to hear that you have made another stove like mine and its doing very well! Our weather is just beginning to cook down to near freezing at night so I think we will begin burning more soon. Looking forward to seeing the new thread.
Thanks to everyone else for your input as well, this is a great place to gather information and get ideas for innovation.
Satamax, have you tried your doughnut idea yet?
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Post by satamax on Sept 11, 2018 23:31:07 GMT -8
Travis, It took me 2 years to try the vertical batch. So don't hold your breath.  CF: My signature! |
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Post by peterberg on Sept 12, 2018 1:15:25 GMT -8
Wow, thanks Peter thats exciting to hear that you have made another stove like mine and its doing very well! Our weather is just beginning to cook down to near freezing at night so I think we will begin burning more soon. Looking forward to seeing the new thread. Hi Travis, The new thread about the tapered riser is already well on its way. See donkey32.proboards.com/thread/3379/tapered-riser-batch-box-core |
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