Vortex Stove

[serg247]

Vortex. More like Peter's DSR. By definition, the Aryan is the upper chamber, where the “ram horns” should be twice as large as the lower chamber. Your top camera is four times smaller and represents a channel.

[Orange]

that is an 1'' vermiculite board around firebox? how hot does it get?

and the double vortex looks picture perfet, I'd put and opaque bottom door just to put more focus on the vortex 

[Vortex]

The white board around the firebox is 1" calcium silicate board, it was meant to be rated upto 1000*C, but cracks up and falls apart if you try and use it anywhere near that. Fine on the outside of the castings though. I have some real pieces of vermiculite board around the top edges of the metal behind the glass, it seems to be holding up fine so far.

The upper glass is the old piece from my original vortex stove door, it's very opaque from years of use. If I decide to keep this setup I'll buy a new piece and make a door for there. Makes a great little oven, just the right size for a casserole dish

[furno]

It seems to me that the volume of the second camera is too large. Flue gas fills this volume and loses temperature, which is needed for afterburning of gases.

[Vortex]

Why would you think that? The 'second camera' as you call it is 1 CSA in size - the same as on a batchbox heat-riser, but there it's round and here it's a rectangle... It has 6" of insulation on the sides and 1" on the top, it glows orange hot and a IR thermometer show it as hotter than the firebox.

[furno]

I supose that pure combustion will be at a high thermal stress of the volume of the flame combustion and high speed movement of the burning gas. . The high value of thermal stress can be achieved with small volumes of the combustion chambe

[Vortex]

Can you give and example?

I've been intending to try a slightly smaller chamber, but in this situation if you make the chamber too small, there is not enough room for reduction in gas velocity after the port to produce the double vortex, as the gasses just stream straight through and out of the chamber.

[furno]

I use the second small camera in my project. donkey32.proboards.com/thread/3413/brick-stove-core-project-furno

However, Peter does not rank it as a rocket. But I do not worry about this. Double vortex is one of many ways to achieve flow turbulence. In my opinion, sharp turns of flow reduce speed. I'm trying to keep the flow rate and create local obstacles to create turbulence.

[Vortex]

I tried a smaller chamber on this mornings burn. 7.5" wide x 4.5" high (Usually 9" x 4.5")

As I suspected there was not enough dwell time, the vortex got squashed into a scissors handle shape, and a lot of it wasn't spinning, just hitting the top and shooting out forward.

The most surprising thing was how much it affected the efficiency, a big difference to the 9" x 4.5" setup. Stovetop and the mass didn't reach anything like their usual high temperature. One burn a day in the mornings has been doing me nicely, and mid afternoon I can already feel I'm going to have to light it again tonight.

[DCish]

Hey Trevor, thanks for tipping me off to this new development, I'd completely missed it! What you describe matches the experiences I've had when I was playing with putting a horizontal port in the side of a batch box. I spent a bunch of time playing with the shape and length of the secondary burner, with all sorts of square and round dimensions. I even cast a tapered afterburner element with two half-cones on either side of the port in an effort to keep the initial afterburner space tight. My thought was that the less space there was for the gases to expand into right after the port, the earlier in the burn the afterburner effect would kick in, and the longer it would be sustained. I still have that piece, and may play with it some more, but in the end, my general conclusions match yours - that a rectangular full-CSA afterburner reliably creates a double vortex, and that a slight constriction following the initial afterburner area helped improve dwell and thus had a positive effect on supporting afterburner stability, even more so than trying to keep space tight with the double-half-cone element. I very much appreciate the numbers that you arrived at, as all my stuff was just eyeballed on the fly.

[Vortex]

Thanks Brian. I vaguely remember your thread, it was this one wasn't it? donkey32.proboards.com/thread/1690/walker-core-variation Unfortunately all the video links are broken, which is a real shame.

My stove is a lot shorter and wider than Peters DSR. The firebox is only 15" deep by 12" high and wide.
How much space do you have for yours?
The firebox would be fine with the door on the side, but a window on the side of the afterburner would be looking at the double vortex side on, so you'd lose that beautiful end on view of the rams horn.

Over the winter I've been trying out a lot of different little tweaks to the afterburner and port, looking for anything that helps keep the vortex spinning in the back of the chamber longer. Most either were a hindrance or at best didn't do anything. The 45 degree bits in the bottom corners helped of course. The other one that does seem to help quite noticeably is this little bit on the inside front edge of the port. I call it the port bow, as it's like the bow of a ship.

[wiscojames]

What's the material, and how's it fixed there? What about another on the bottom?

[Vortex]

It's just made out of a small off-cut of 2" angle steel. I had the idea a couple of weeks ago and wanted a quick easy way to test it out. It's just held there by gravity as the 2 corners are slightly wider than the port. (That picture is looking vertically up through the port into the afterburner. The top of the picture is the front of the stove, bottom is the rear.)

I wondered about having one the opposite way around on the other end, or maybe have the afterburner chamber very slightly farther back so there's a little step back above the port.

[fig]

Do you prefer your new version to your old one? Are you sharing dimensions as you did the old stove? I was considering building your older version but I like your newer one too. Is it more efficient? Tia.

Fig.

[Vortex]

Hey Fig. I like them both, but this is definitely more efficient. Being able to see the afterburner teaches you how to get the best efficiency out of it, as you see and feel the immediate results of your actions.

I miss having 2 fires a day like I did on the old stove, I can only light the new one once a day unless the weather's really cold, otherwise my house gets way too hot. On the new version of the old stove I liked watching those downward gas jets, but watching the double vortex more than makes up for that.

I originally built my woodshed to hold enough firewood for a winter. The new stove cut my usage down a third, and now with the Aryan afterburner it's cut it down another third. I'm getting old so having to only cut a third of the wood every year is a great bonus. At present rate I'm going to burn a little under 1 cord of wood a year with the new setup.