need feedback for my design for cooking plate AND oven?

[lawry]

I don't understand your riser diameter. How many inches is it?
-The circumference you use is the circumference that your gasses go over. If you direct them in a channel in one direction then they will go over half the circumference. If it were a barrel over the riser then you would use the complete circumference
-The resulting number just maintains your system size (csa)
And it helps so that you don't restrict the flow by making it smaller. If it's too larger then the flames may not touch the top...

[satamax]

Well, get back to the basics.

CSA, or cross surface area is the surface you have, cut across a tube perpendicularly So

Diameter² x PI= .../4 Or radius² x PI

Then you have the circumference

diameter X PI.

Then you have the ring projection. Imagine as if the walls of the tube were projecting into the gap's space.

You have the circumference of your pipe, multiplied by the gap height, which gives you the "ring projection's surface"


And this ring projection's surface should be at least 1.5 times the csa for a J tube rocket. I usualy say 2 or 3 is better.

For a batch, Peter advises that the gap equals the diameter. So a 6 incher would have a 6 gap. Tho, i have goten away with smaller gaps myself.