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Post by satamax on Sept 12, 2012 11:02:02 GMT -8
Peter, it cleared up today, and i just thought about what i said! You might know Rochebrune and Galibier. Yep, that's today! ;D |
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Post by koldenburg on Sept 12, 2012 15:52:36 GMT -8
Peter thanks for all the information. I've really enjoyed reading through your various experiments. Any suggestions on what model to resize or utilize for a small space? The latest variation seems to make experimentation easy but locally I only have Chimney blocks with an interior diameter of about 350mm. There is availability of larger clay chimney liner tiles but I'm not sure how they would hold up. I also have a testo gas analyzer so I'm very curious to take some measurements once it's functional. Thanks much.
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Post by peterberg on Sept 13, 2012 5:53:14 GMT -8
Peter, it cleared up today, and i just thought about what i said! Sweet memories... I've been there in late October, spring and autumn. Years and years ago, last time in 1997. Hasn't changed a bit, as far as a picture is anything to go by. |
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Post by peterberg on Sept 13, 2012 6:03:28 GMT -8
I've really enjoyed reading through your various experiments. Any suggestions on what model to resize or utilize for a small space? Hi koldenburg, welcome to the boards. A tried and tested stove size for a small space could be the rocket mass heater of last year. Depends on what you want, of course. Mass storage or not, that's a fundamental question you have to ask yourself first. The chimney blocks are alright for a bench in my opinion. |
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Post by satamax on Sept 13, 2012 11:10:23 GMT -8
Peter if you're around, would this P chanel arangement work? Attachments:
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Post by peterberg on Sept 14, 2012 1:16:06 GMT -8
Peter if you're around, would this P chanel arangement work? Max, I'm afraid it won't. This construction will heat up the air far more, running the risk of not going down to the tunnel so easily. The construction running the horizontal part over the ceiling part is a safer bet. This is gut feeling only, no tests has been done to proof this. |
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Post by satamax on Sept 14, 2012 1:38:10 GMT -8
Thanks a lot peter!
Well, something which just popped in my head, do you know EGR? Exhaust gas recycling? In cars, where they feed proportion of exhaust gasses back in the intake. Taking the P chanel gasses from the bell instead of from the outside. I know this might sound daft, and i haven't thought about this regarding presure differential etc. But that popped in my head. Not much O², as well.
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Post by satamax on Sept 15, 2012 10:01:44 GMT -8
Time to carry on hijacking this thread. I went on the other side of the border. Well, they didn't have any 25x25 square, so i've taken some 30x30. Peter, what do you reckon, cut five cm of the width? Last time for two 16cm tubes, i've paid around 50 something euros. This time, 12 euros, for a 16 and the 30x30. Weird how they do the pricing. ;D Attachments:
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Post by peterberg on Sept 15, 2012 14:03:06 GMT -8
I went on the other side of the border. Well, they didn't have any 25x25 square, so i've taken some 30x30. Peter, what do you reckon, cut five cm of the width? Max, Maybe it's not important whether or not the sides of the riser have a close fit to the inner sides of the firebox. What I'd think is really important, on the other hand, is the rounded sides of the riser inside the firebox. I've mimicked your construction a few days ago in a scaled-down steel item. The thing started in a very promising way but refused to run properly, no matter what. I'd think the reason is this: the deeper sides left and right of the tunnel opening create a small under pressure which will slow the stream down constantly. To avoid this effect, you have to fill in those cavities. |
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Post by satamax on Sept 15, 2012 23:55:57 GMT -8
Thanks a lot Peter.
Well, that was the plan anyway. Since i'd like a longer burn tunel than the 30ish cm of the first iteration. I have to put the heat riser at the back. So a back burn tunel wall is in order.
What do you think about the question? Do i leave the 30x30 square as is, with slanted bottom? Or do i cut it so the width is only 25cm. Or even 20. for that 2/3 ratio? I'm trying to figure a way to see if 30 full width would work.
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Post by peterberg on Sept 16, 2012 7:53:04 GMT -8
Do i leave the 30x30 square as is, with slanted bottom? Or do i cut it so the width is only 25cm. Or even 20. for that 2/3 ratio? I'm trying to figure a way to see if 30 full width would work. I'm inclined to say: make the width 25 cm (10") or whatever is convenient to you. A vertical divided firebox is probably best to avoid heat cracks, being the main reason. |
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Post by peterberg on Sept 17, 2012 0:57:44 GMT -8
Progress has been made with the batch box rocket stove. One of the people from a forum in the Netherlands picked up the idea of a refractory core. His second mold resulted in a one-piece core, albeit he had to burn the mold out of it. Because he wanted some figures how the thing would perform, he's brought it to my place. This implementation sports an octagon lower riser part, simple p-channel like my last one and a riser length of 5" refractory and 20" of insulated stainless steel. This is significantly shorter than my own fire brick set-up, which added up to 34.5" above the port. No restrictions of going from rectangle to round, octagon is a very close approximation. And lots of space above the riser, of course.  High res:In order to extract more heat we've added a second 55 gallon barrel. The exhaust of these is at the back, close to the bottom of the lower barrel.  High res:The refractory core wasn't dried at all yet, in fact it's been cast late Friday night. Despite that, we've done a testrun, firebox filled just over half. See these video clips for the looks and the sound of this burn. During the second clip there's a clattering noise, caused by the piece of glass which rattles against the front of the casting. Of course I've performed this run with the Testo sampling and logging the data. This is the resulting graphic:  High res:Not bad, not bad at all. Especially when taking into account the fact that the thing wasn't dried out at all. The average numbers of this run: O2 12.9 %, eff. 84.5 %, CO 1103 ppm, Tr 153 C. (307 F.). The amount of glowing embers was a bit too much to my taste, probably due to the moist in the casting. Edit:Just in case anyone is wondering where the fan would be installed: there's none at all. And no, the casting didn't hold up to this violent burn. The top and rear parts cracked because of heat expansion. Hottest spot is the lower 6 or 7 inches of the riser, so next incarnation will be a core in two pieces. |
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Post by satamax on Sept 17, 2012 4:44:45 GMT -8
Nice!
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docbb
Junior Member
Back from ZA
Posts: 92
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Post by docbb on Sept 17, 2012 17:26:56 GMT -8
dear Peter,
-have you any picture of the crack?
-are the measurements made with or without the glass ?
and
don't you think that kind of a surface treatment in the port would smooth the flow, like a zigzag tripwire or a"golf ball" surface ?
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Post by satamax on Sept 17, 2012 22:54:52 GMT -8
Doc, i don't think Peter wants to smooth the flow. The principles of a good burning rocket is turbulence, lots of it. So every remaining particle of gasses is burned. Besides, if i remember well from my moped tuning days, there's laminar flow, the surface of any material slowing down the air movement next to it, to nearly standstill, then the next layer goes a bit faster and so on untill about 3cm away you have nearly no drag from adjacent layers. Well, that's if i recall correctly. I have proposed to make the venturi edges rounded, but Peter says there's not much to gain there. IMHO, there might be,increasing the flow speed, but the question is, is it realy nescessary? If there's too much oxygen leftover, it's cooling the burn, which we don't want. And since i don't have a testo or any kind of testing equipement. I'm refraining from doing deviations ;D
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