Just an odd query re Stirling engines:
While I have "read a book and other stuff", I had a thought to own a Stirling engine, so I could play about a bit and get to appreciate its fundamental thermodynamic beauty.... (remove tongue form cheek?). So I bought a cheap device from China. Nice little toy, except the Pyrex glass tube has melted and deformed a bit while attempting to make it run. The plans had a displacer made from a "cylinder" of steel wire wool on a piece of piano wire (con-rod), but this is porous, so carried a lump of steel from Hot-to-cold-and-back, without any appreciable volumetric displacement of gas.
Anyhow, it didn't work.
So I have made a nylon displacer (because that's the material I had in that size). it still doesn't work.
It doesn't even attempt to do any work.
Check the timing: Set the displacer to LEAD the power piston by 90degrees. Correct to a "good eye"...
Friction? - Minimised, a flick of the flywheel and it spins for a lot of revolutions...
Suggestions of what may be wrong please?
Thanks,
K2
Hi K2 !
Looks like we talked about your engine problem in another thread
My experience with small stirling engines is limited to the engines I've done, so:
A stirling engine depends on the volume change of the air inside the engine when the air goes from the hot zone to the cold zone and vice versa and with engine rotation - several hundred rpm - that results The volume change of the air inside the engine is very small - extremely small - and almost instantaneous, so:
- Friction, not smoothness
- Airtight
The above 2 causes will kill it
Friction must be reduced, to the minimum that the engine can keep running
The engine must be airtight : at the joints, between the cylinder and the power piston, between the displacer's connecting rod and its bearing.
"Airtight" between the cylinder and the power piston, between the displacer's connecting rod and its bearing:
that's really a problem, you have to make sure they're all smooth together BUT they have to be "airtight"
I put "airtight" in quotes because that tightness isn't completely airtight but it's good enough that
small changes in the volume of the air inside the engine affect the power piston.
Displacer: is a part to move the air inside the engine from the hot zone to the cold area and vice versa., so make its weight as light as possible and suitable for the temperature of the engine.
Power piston: just a part that reflects the change in volume of the air inside the engine