Is it possible to use a rocket stove to produce a small flame, e.g., similar to that by a kerosene lamp? I'm trying to warm a kettle of water to around 50C (without boiling) overnight using a self-feeding mechanism/stove, and it seems that a rocket stove is probably a common one? The flames I've seen on Youtube are fairly large though.
Glenn Herbert wrote:Probably not, unless the kettle is really big. A rocket stove burns fast and hot, and cannot be damped down to a trickle without destroying its clean-burning characteristics. As the system size gets smaller, it becomes less stable and more subject to friction and surface loss effects; it *might* be possible with a bunch of experimentation to build a very small self-feeding rocket-style stove if you have good draft and do not try to heat a thermal mass. What kind of fuel are you thinking of, and how big is your kettle?
It'll actually likely be a coil-based design like
I'm thinking of using just twigs as fuel.
John McDoodle wrote:small rockets require almost constant feeding- especially burning twigs. since you said you want to heat water overnight keep that in mind... i would put the coil on the exhaust chimney if i wanted to "avoid boiling"
Oh. Do you know why small rockets require constant feeding (even for a small flame)? Does that mean efficiency is high only when the flame is large?
im actually uploading a youtube video right now of my rocket burnin on solely twigs found outside here in canada in winter. it should be public within the next half hour or so....
I see two issues with your sketch aside from fire duration.
The inner shell you show, if it is metal, will deteriorate quickly if it is well insulated on the outside.
A copper coil wound around the inner shell will be exposed to 1000-1500 F temperatures regularly depending on how closely it hugs the shell, and at that temperature you have an extreme risk of the water in the coil flashing to steam and exploding the coil.
You still would be looking at high-temperature combustion, just controlled to a slower rate and smaller fire if desired.