Date: Sat, 04 Jul 2009 09:13:55 -0400
To: Dave Misiuk <dave(at)cchrc.org>
From: Norbert Senf <mheat(at)heatkit.com>
Subject: Re: Rocket Stove
Cc: Alex Chernov <alex_stovemaster(at)yahoo.ca>, fishermasonry(at)yahoo.com, William Davenport <info(at)turtlerockheat.com>, Ksenia Chumakova <aksinia(at)gmail.com>, "Brian Klipfel" <b_klipfel(at)hotmail.com>
At 04:00 PM 7/3/2009 -0800, Dave Misuk wrote:
The rocket heater looks like it was a cool experiment.
Do you have any pics of the firebox "guts," i.e. does it open directly into the large bell?
yes, directly into a single large chamber
My instinct would be to also have a secondary combusion chamber (1st bell) and then the larger bell.
Yes, wanted to keep it simple to see what happens.
I think on this one, with the narrow chamber, it is partly like a channel, and you get jetting action.
Ie., the momentum effects out of the firebox are pretty high in relation to the buoyancy effects.
With a wider chamber, I'd expect more buoyancy, less momentum. I wouldn't have predicted the result,
although it seems fairly obvious in hindsight.
It was an impromptu design, based on a 9" firebrick and no cuts. The original idea was to train Ksenia on the
Condar, get an outline written down, so that we would have a start on that project for MHA. Time constraints
intervened.
It is an interesting enough heater to keep around for awhile, already thinking of some mods.
I'd love to learn to model it in CFD, since it is a simple design.
I'm thinking to have the flame jet hit a vertical wall of insulating board, thus shooting it up. I'd
guess a drop in stack temp and higher efficiency. It'll create a hot spot on the bricks, so maybe line
all 3 sides with insulation, maybe 12" or so into the chamber.
You could easily add a sheetmetal divider from the top, creating two bells, side by side. The first bell
would exit at the bottom. If you didn't do the vertical flame diverter, the flames would probably shoot
straight through, otherwise.
And I would have put a lid on the firebox so you can have an air intake damper.
Yes. We did do that, with loose firebricks. 7" slot one or two inches wide works good. Stack temperature drops
maybe 50 degrees. Oxygen drops, but only a little. So, maybe 5% efficiency gain. Haven't crunched the numbers
yet, hopefully today. Efficiency seems roughly in the 50 - 60% range.
It was a gnarly heater to get started. No hairlining though............Norbert
Dave