Glossary of Terms

[Donkey]

BTU British Thermal Unit (symbol Btu or sometimes BTU) is the amount of energy needed to heat one pound of water by one degree Fahrenheit.

Bell A chamber used to extract heat from exhaust gasses through contact with large surface areas.
See Donkey - Interesting huh? More good Bell stuff

Burn tunnel The (usually horizontal) section of a rocket stove where the primary stages of combustion take place. Shown at the bottom of this RMH cutaway

Batch box Horizontal burn, tunel, like L shapped rockets for cooking, enlarged with a smaller port at the back, where it meets the heat riser. Intended to load more fuel.

Cob A building material made from clay ( clay-rich soil) , sand and straw.

CSA Cross Section Area The area inside a section of the heater through which gasses pass.
Example 8” pipe, (pi)(radius squared) CSA = 50.24 sq. inches 8” X 8”, CSA = 64 sq. inches

Flashover The portion of the burn where the entire heat riser is filled with flame.

Ianto Evans / Leslie Jackson Rocket stove designers & advocates. You can buy their book here. Their web site

ISA Internal surface area of a Bell, area which exchanges the heat from hot gases to cooler massonry or steel, which in turn exchanges heat with the surounding air. Not to be made too big or the stove stalls (stops)

J tube rocket Rocket stove with the horizontal burn and riser sections forming a “J” shape.

(p) Peter channel A channel that allows secondary combustion air to be pre-heated in, and exit right in front of the burn tunnel resulting in more complete burning of combustion gasses.
P - Channel

pyrolysis The chemical decomposition of fuel by heat without oxygen.

RMH Rocket Mass Heater A rocket heater with sufficient mass to absorb, and store, combustion heat and release it gradually.

Riser The vertical section of a rocket stove where combustion takes place at high temperatures, resulting in increased burn efficiency and lower emissions. RMH cutaway

RSJ - Rolled steel joist; steel "I" beam

SketchUp 3D modeling software Download free version here

Testo Manufacturer of electronic measuring instruments.
Testo Testo measurments made by Peter

Trip wire A feature that projects into the burn tunnel, ahead of the riser, to create turbulence in the smooth (Laminar) flow of gasses, to mix unburnt gasses with oxygen-containing gasses in order to achieve more complete combustion. Good Trip wire discussion

Trip wire brick Tripwire cut into a brick . Trip wire brick

Venturi effect A jet effect; as with a funnel where the velocity of the fluid increases as the cross sectional area decreases Venturi effect

[petect]

Better?

Attachments:

[Donkey]

Mar 4, 2013 8:25:46 GMT -8 petect said:

Better?

Yep..
I got all annoyed with your drawing and had to go look at Ianto and Leslie's book (it's been a while).. After a good look, I have to admit that your drawing is accurate...

After a couple of days of sitting on that thought, I've realized that what's missing is a good explanation of WHY the dimensions are given as they are in the book. As always, these things are a compromise between competing limits, competing needs, etc.
The intent of the design and measurements as given in the book was to create a "baseline model", a "works more often than not with minimal fussing" kind of stove. We also wanted to keep the stove description simple and not overly technical, the book is for the unwashed masses so it needs to be accessible in language, etc.
At the time of it's first release (the book), I wanted to see a more in-depth explanation of the physics and whatnot going on inside the J-tube. Ianto and Leslie were of the opinion that too much of that kind of thing would be inappropriate for that particular book. Now, I'm glad that they held firm to that principle, they were right and it's a better book for it.

One of the issues with the way the dimensions are stated is that it leaves the impression that the CSA of the burn tunnel MUST be smaller than that of the heat riser, ditto for the feed.. I've seen some designs that misunderstand this point to an extreme level.
Really, these should be considered in the "fudge factor" of it all. The ideal that we're shooting for is a CONSTANT CSA throughout the J-tube, but realizing that the act of actually building one of these out of brick can be highly imprecise; the rule is, if you've got to fudge it, fudge it smaller towards the feed side of things.

[petect]

ALL very true. But I think a glossary is for the new guy who is trying to get a handle on things. So I'm trying to abide by K.I.S.S. Otherwise, if you start introducing all the possible variables, the simple soup can rocket, which IMHO should be a fun learning tool, can become almost impossible to understand.

Yes the WHY is very important, but I think those who are truly interested in the why will read Ianto and Leslie's book and all of the posts here.

Pete

[Donkey]

Yep.. Good point, which is why I finally came to be glad that they kept it simple in the book..
Not everyone gets fired up by the nitty-gritty geekness of it all..
That said, I still think that some explanation is in order, otherwise people take the statements TOO seriously and end up designing some really ridiculous things..
And, the explanation can be pretty simple, something along the lines of what I finished the post above with..

The ideal that we're shooting for is a CONSTANT CSA throughout the J-tube, but realizing that the act of actually building one of these out of brick can be highly imprecise; the rule is, if you've got to fudge it, fudge it smaller towards the feed side of things.

Or something.
??

[domovoi]

Leslie, the aforementioned, here. Hi. Glad to read these posts. Donkey, I like your discussion of the CSA consistency, and will steal some Ianto-compatible version of it from you for the next edition. It is a masonry stove principle, not just Ianto's and can be found in David Lyle's book too.

I hope this is a sufficient place to say if there are words you (or any forum members) would like to quote from the book, Rocket Mass Heaters, feel free, simply site your sources, and if you point to the book's site, www.rocketstoves.com, we really appreciate it!

Great discussion!
Leslie

[Donkey]

Thanks, Leslie!!

[petect]

Yo Donkey
I've been tied up with work lately. I'll modify and repost the J Tube drawing when I get a chance.

NOW here's the question. Do you think it would be best to put images in the glossary, (if so I don't have a clue how) OR start an Images index. Put it there and add a link to it from the glossary?
I think it could be usefull to have a place to put drawings of stoves, moulds, etc that are buildable.
Pete

[Donkey]

Hmm..
Both sounds right to me.
I'd put VERY SMALL images into the glossary, clarifying images only. Keep them below, say, 300X300 pixels. Simple graphics that illustrate the text.
I like the idea of a repository for designs and/or higher rez descriptors/WIP/finished images. These can be linked out to the index as needed.
The way to get your images in-line with the page is: link to an image on an internet server somewhere. Images would be uploaded to the web server, then tags aiming at those images are put in here in the form of BBcode. Looks like this:
[img]http://www.pberg.demon.nl/pictures/PD/RB-PD1.jpg[/img]
This image is on a server, in the Netherlands, that Peterberg uses.

The image tags (img, with square brackets) mark the start an the end of the link. Don't forget that ALL links, to be valid, need to have an opening and closing tag, the closing tag has a slash in it.. /
The image tag above renders on the boards like this:

[doggy1969bc]

temperatur conversion celcius to fahrenhiet
Tf=Tc . 9/5+32
Tc=(Tf-32)5/9

[Cramer]

RSJ - Rolled steel joist; steel "I" beam.

Hey Donkey, as terms like these are added in this thread might it be a good idea to add them to the original list of terms via the edit option (open only to you of course) so that that list becomes more comprehensive as a "Quick Reference"?

As an example this term was used in a thread (RSJ), and knowing this thread existed because I was pointed to it earlier I immediately came here in search of the definition for the abbreviation.  It wasn't here though so I had to have it cleared up in the thread itself which took a day.  So in case someone else wondered and knew of this thread I thought to post it here.

Another thought comes to mind, it might be a good idea for this list to be included in the "Start Here" thread with terms such as Batch Box (also not on the list) included so that someone just beginning research on these Dragons (another term that might be whimsically included in the list) might immediately gather a base of knowledge from with to begin.  Just my two cents worth, up to you of course but it might keep this thread from becoming unwieldy and increase the user friendliness of the boards in general.

[Donkey]

I like your request quite a lot. On that note, I've given the responsibility of maintaining this portion of the board to others.. They have the powers to do what you are asking as well..

Also, be careful about how much stuff you ask for and how good your suggestions are.. If you impress too much, you may end up with powers and responsibilities too..

[Cramer]

I like your request quite a lot.

Thanks for the giggle!

Hey Donkey... I would like your comments on this thread if you get the chance sometime.

donkey32.proboards.com/thread/1044/working-backwards-bell-burner?page=2&scrollTo=9563

[satamax]

Okay okay! I'm off to work

[Daryl]

I'm bumping this up.  Great fundamental information for everyone who is a newbie.