Why? Something being explosive doesn't have a lot to do with it's rate of expansion unless you intend for it to explode.
Leidenfrost heat engine
Re: Leidenfrost heat engine
"Volatile" when referring to a substance, in this context simply means that it transitions from a liquid to a gas, (boils or evaporates, changes state) readily.
An explosive expansion is what is wanted in an engine to drive the pistons, generally.
The problem is that such explosive expansion, as is standard and commonplace in an IC engine has been difficult, to near impossible to achieve in an external combustion heat engine.
Engines RUN on controlled explosions.
One problem I'm noticing, which I'm not sure if it will be a problem in a running engine is; fresh out of the freezer, if I set the pop bottle with the condensed liquid butane down where air flow around it is blocked, it tends to just sit there in a cold crumpled up state, without taking in much heat for expansion. If I pick it up, so there is more air circulation around the bottle, it then will expand rapidly.
Fresh from the freezer, some liquid butane can be seen to have accumulated.
Sorry, the picture is blurry, but I don't have much time to focus. A few seconds later that bit of liquid butane evaporated, re-expanding the crumpled bottle.
An explosive expansion is what is wanted in an engine to drive the pistons, generally.
The problem is that such explosive expansion, as is standard and commonplace in an IC engine has been difficult, to near impossible to achieve in an external combustion heat engine.
Engines RUN on controlled explosions.
One problem I'm noticing, which I'm not sure if it will be a problem in a running engine is; fresh out of the freezer, if I set the pop bottle with the condensed liquid butane down where air flow around it is blocked, it tends to just sit there in a cold crumpled up state, without taking in much heat for expansion. If I pick it up, so there is more air circulation around the bottle, it then will expand rapidly.
Fresh from the freezer, some liquid butane can be seen to have accumulated.
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Sockmonkey
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Re: Leidenfrost heat engine
Ah, gotcha. Plastic doesn't conduct heat as well as metal, and the movement of the piston will stir things up so it probably won't be an issue in an actual engine.Tom Booth wrote: ↑Sun Jun 28, 2020 11:49 am "Volatile" when referring to a substance, in this context simply means that it transitions from a liquid to a gas, (boils or evaporates, changes state) readily.
An explosive expansion is what is wanted in an engine to drive the pistons, generally.
The problem is that such explosive expansion, as is standard and commonplace in an IC engine has been difficult, to near impossible to achieve in an external combustion heat engine.
Engines RUN on controlled explosions.
One problem I'm noticing, which I'm not sure if it will be a problem in a running engine is; fresh out of the freezer, if I set the pop bottle with the condensed liquid butane down where air flow around it is blocked, it tends to just sit there in a cold crumpled up state, without taking in much heat for expansion. If I pick it up, so there is more air circulation around the bottle, it then will expand rapidly.
Fresh from the freezer, some liquid butane can be seen to have accumulated.
IMG_20200628_141817075_crop_73_resize_36.jpg
Sorry, the picture is blurry, but I don't have much time to focus. A few seconds later that bit of liquid butane evaporated, re-expanding the crumpled bottle.
Re: Leidenfrost heat engine
I can report that my attempts to power an LTD on ice, charged with butane, using ambient heat, have been a complete failure.
My general impression is that a lot of heat is required for phase change, which is why a butane rocket needs a lot of water, which can hold a lot of latent heat.
Without some means of delivering a lot of heat all at once to the liquid butane, it is rather like trying to boil a pot of water with heat of the hand. There is no rapid phase change.
My general impression is that a lot of heat is required for phase change, which is why a butane rocket needs a lot of water, which can hold a lot of latent heat.
Without some means of delivering a lot of heat all at once to the liquid butane, it is rather like trying to boil a pot of water with heat of the hand. There is no rapid phase change.