Post by invention1 on Jan 25, 2018 18:57:28 GMT -8
I wonder which of the dimensions given are most critical?
I can see how the primary air, secondary air, and the riser area should be directly related. Port dimensions should be rather critical. Firebox width and length help govern how much turbulence is developed at the port. I plan to stay "by the book" for these dimensions when I build something.
I wonder though how critical the length of the batch box is. I kind of favor building a long stove so I can save my back on woodcutting. Firebox length dimensions given for a 6" stove would be 17-1/4" , and batchrocket.eu gives a range of 4 to 5.5 times base, or about 17-1/4 to 23-1/2. What would be the harm in rounding that up to a 27 or 28" firebox, given everything else in the stove is "to spec?" Is there something that this would throw off?
Last Edit: Jan 25, 2018 18:58:27 GMT -8 by invention1
Anyone who says I am on a fool's errand is probably right.
Post by invention1 on Jan 25, 2018 19:19:23 GMT -8
What about dimensions of air inlets in a smaller stove? Does boundary effect choke them off?
Say I'm building a 6" batch rocket stove, which needs a Primary air opening of 5-5/8 sq in area. Say it's primary air opening is 8" wide, about the same width as the firebox, making the primary air height theoretically 0.70. Would that actually have less than 5+ sq inches of free area due to boundary layers at the long skinny opening? Might that starve the stove for primary air even if it was the right area by the ruler?
Same question might be applied to the "Peter Plate" in a J rocket. This is a long, skinny opening. Even if it theoretically has the same 5% of Riser Cross Sectional Area as you'd use in a batchrocket, an 8" wide "Peter Plate" sized at 5% of riser CSA for a 6" riser stove would need to have 1.875 square inches open area, or a gap of 0.23". Would that really provide enough air or would it need to be opened up by 1/8" or more to get past boundary layer effects on the edges?
What would be the symptoms of a stove that didn't have sufficient primary air? Would it show up in slow wood consumption, or would you need a Testo to prove it wasn't burning right?
Anyone who says I am on a fool's errand is probably right.
Look at this picture, there's a triangular piece of steel on top of the entrance of the floor channel. The single air inlet is at the level of the channel, since there's a distance of around 30 mm between the door and the threshold, the primary air is going up and over. Is this enough information?
Last Edit: Sept 4, 2018 9:03:04 GMT -8 by peterberg
I profited of a short night to extend the values in the Batch-Box dimensions file. There may be some mistakes because i have feel easier to do my own calculation than to find them if they even be here (the "search" function is not my friend, giving me lot of absurd results, or nothing, most of the time). Here's what i've added:
- the maximum box's length: 5.5xbase - the floor channel dimensions, but it's only by memories, i'm not sure, and the horizontal is missing: height=1/2port ; vertical section=PAarea/5 - an estimate of the power of the stove with Peter's recommendation, extrapolated from the below - an estimate of the power with the max length, calculated whith some data from Uzume - the ISA, calculated with the value of 5.3m² for 150mmø riser, verified with the value of 9.4 for the 200mmø. As i get it pretty close i suppose my math are good.
But i'm a nasty frog, so the first thing i did is to suppress the imperial measures ￼ and add a whole lot of metric's ones, each 5mm from 75 to 170, and each 10mm until 300mm. I'm certainly not some kind of perfectionist guy, i just do it 'cause it will be absolutely useful for everyone, don't you think?... No?.... Okay, i don't know why I've done that much, but it was so easy I could'n't resist. The result is that it's unusable for the imperial guys, and barely usable for the metrics guys who intend to make a big stove because the headings disappear as soon as you scroll on the bigger values.
No joke, it's my first time with this kind of software, that's why I've made some stupid things, sorry. If that seem interesting, maybe someone much skilled than me can improve this thing: by rounding the numbers, restore the imperials, find some way to have the headings multiple time or floating, etc.. Also if you say me the missing value for the floor channel, or any error that occur in my math, I will correct it. For the power value i'm very doubtful of the accuracy, but only find those of Uzume.
At least, the file: .ods is the default extension open office purpose to me.
.xlsx is the original extension of the file from here.
p.s. : is there still anyone who use the P-Channel? I wonder if it's useful to still have those values...?
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deadstarsstillburn: but I do not need to heat all of it by any means. probably only need to heat half of that, maybe less.
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deadstarsstillburn: moreover, the house has 3 storeys (large attic) so I assume if I get very efficient heating on the ground floor, that will go a long way toward heating the upstairs as well, no?
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