Could Both Carnot and Tom be Correct?

[Tom Booth]

... But please continue with late posts,...

...
(1) be 'late to the party' ...

The fifth post on the first page you two idiots consider "late to the party".

Can there really be two delusional idiots obsessed with "Tom Booth" both having the same delusion?

So which one of you two is the others "sock puppet".

[Tom Booth]

My memory of that conversation is that buffer pressure doesn't affect the calculations for efficiency. It very obviously affects the running of the engine. It primary effect is reduction of flywheel mass.

...

Is that some kind of typo perhaps?

The buffer pressure's "primary effect" is "reduction of flywheel mass".????

Fool's grasp of physics is really astonishing, but giving him the benefit of the doubt, assuming that is some typo or misstatement or maybe a auto-correct snafu of some sort, perhaps he can explain what he meant to say. Or on the other hand, defend the assertion that buffer pressure can somehow reduce the mass of the flywheel.

[Fool]

Design parameters.

[Tom Booth]

Design parameters.

Most Stirling engines with "buffer pressure" i.e. hermetically sealed, are "free piston".

So, how buffer pressure reduces flywheel mass where there is no flywheel is a bit of a mystery.

Even an atmospheric type Stirling engine can operate with the flywheel removed, as I have demonstrated in some of my videos:

Infact I have an entire playlist on the subject:

https://m.youtube.com/playlist?list=PLp ... qzm1QCGCEW

Anyway, thanks for the clarification, that at least makes a bit more sense.

[Fool]

The mass of the piston stores energy similar to a flywheel, at a much reduced mass momentum.

The mass and springiness of the air/gas also stores energy similar to flywheel. The oscillations are evidence for that. The tuned exhaust pipe principle, for example.

Without an atmosphere or sealed pressurized chamber, buffer pressure, those wouldn't run. I know we already know that.

Without a crank or flywheel we are sort of 'cheating' calling it a Stirling, but I get what you're saying. I am wondering if those open air no moving piston, laminar flow, engines are running more of a Carnot Cycle than a Stirling Cycle?


.

[Tom Booth]

The mass of the piston stores energy similar to a flywheel, at a much reduced mass momentum.


.

Not the same thing

A flywheel MUST return the energy put into it as a consequence of it revolving on a crankshaft.

An open to atmosphere "free piston" Stirling has no such "stored energy" in the atmosphere. The atmosphere has an unlimited capacity to absorb such energy and it's pressure is not increased one iota as a result of its displacement by the piston

The only possibility for the piston to return is by a reduction of energy taken out of the "working fluid", internally, either by "work" output or heat transfer, so that the energy level falls below that of the surrounding atmosphere, not by "stored pressure" in the atmospheric "buffer".

The atmosphere does not "store energy similar to a flywheel".

[Fool]

Not the atmosphere as a bulk entity. The air rushing in and out.

[Fool]

The piston mass and momentum combined with the elasticity of the air or gas has an inherent frequency of bounce.

[Tom Booth]

Not the atmosphere as a bulk entity. The air rushing in and out.

The atmosphere is not going to "rush in" unless it is following or pushing the piston.

The working fluid pressure must first loose sufficient energy before that's possible. Call it elasticity or what you will, there is no "stored energy" from the engine in open atmosphere, just the existing atmospheric pressure.

[Fool]

The atmosphere rushes into a jam jar pulse jet. The same happens for the piston less laminar flow Stirling.

[Tom Booth]

The atmosphere rushes into a jam jar pulse jet. The same happens for the piston less laminar flow Stirling.

Great, so where is the buffer pressure and how does it reduce the mass of the flywheel in the jam jar engine?

[Fool]

A jam jar jet engine's buffer pressure is the atmosphere, 14.7 psi. It has reduced the need for a reciprocating and or rotating mass to the mass and flow of air fuel mixture in the jar. It's oscillation is a function of the size of jar, hole, and type of air and fuel.

It fires, exhaust starts rushing out of the jar because it's hot and at high pressure. Constant temperature heat addition. Bang.

The mass of air develops momentum that keeps it moving out after the pressure lowers in the jar to atmospheric/buffer. That continued momentum lowers the pressure below atmospheric/buffer pressure. In other words producing a partial vacuum. Adiabatic temperature decrease. Blow.

That lower inside pressure and higher outside pressure, causes the momentum to slow to a stop and reverse flow. It develops momentum while rushing in, while pulling in fresh air that mixes with fuel. Constant temperature heat rejection. Suck.

The momentum keeps the fresh air coming in and mixing with fuel, until the the pressure builds up higher than atmospheric. Adiabatic temperature increase. Squeeze.

The squeeze and hot fuel increase the temperature until above the ignition point. This starts the cycle again with a bang. Constant temperature heat addition, again.

Bang. Blow. Suck. Squeeze.

A laminar flow piston-less Stirling Engine does the exact same thing minus the fuel mixing and bang, more of an almost pop. It needs it's 'blow' and 'suck' momentum boosted by having a narrowed section of tubing between the hot chamber and cool outside atmosphere/buffer pressure.

That narrowed section is equivalent to the flywheel. The energy storing mass has been reduced to the air mass. The squeeze adds to the the heating in an adiabatic like process making this a real world non ideal Carnot engine. The cooler is replaced by the sucking in of cold atmospheric air. So an open cycle Carnot.

Special note of curiosity: I predict that a laminar flow Stirling could be made at a higher buffer pressure by connecting two hot chambers to a double sided cold chamber in between the hot section for a closed system. I visualize it being linear three chambers

(R hot R)===(R cold R)===(R hot R)

But it could be bent. That would put the hot chambers in the same furnace and the cold chamber far away and outside.

The () are the end walls.
The === are the narrower interconnecting tubes.
The R are optional Regenerators. Yes I've thought of other positions for, and numbers of, regenerators.

(R hot R)===(R cold R ¥|}
(R hot R)===(R cold R ^|}

¥^|} indicating one cold chamber, but not limited to one, and interconnected. This configuration would reduce shaking force.

Sizing the tube's diameter and length with the chamber's diameter and length and regenerator size and position would be used to tune for a specific frequency. With, or without regenerators, would, perhaps, be the difference between Stirling or Carnot, respectively.

Harvesting effective work could be done using magnets, or metal, or coils, inside and or outside, of the chambers and or tubes. Careful design would be very necessary here as well. Any mass inside and harvesting of energy will change the tuning. Maybe the whole thing could be put on a pendulum, or shaker frame tuned to the working frequency. Crank and flywheel are options too.


.

[Tom Booth]

So how does the buffer pressure in a hermetically sealed and pressurized NASA free piston engine at 35 bar reduce the flywheel mass?

[Fool]

It reduces the mass if the buffer pressure aids in returning the piston to top dead center against the pressure of compression. The buffer pressure provides partial return stroke work.

If there were a vacuum on one side. The power stroke would be more powerful, but the return stroke wouldn't provide any work. Vacuums don't push. So all the work necessary to return the piston, against the cooler lower pressure gas, would need to come from stored springs and momentum, requiring stronger springs and more mass. Again it a design parameter, having or not having a buffer pressure.

Adiabatic temperature drop from work.during expansion, becomes adiabatic temperature increase during the return stroke And uses the same amount of work to accomplish the compression.

Only heat rejection will reduce the work requirement for the return stroke below the power stroke.


.

[Tom Booth]

...

Adiabatic temperature drop from work.during expansion, becomes adiabatic temperature increase during the return stroke And uses the same amount of work to accomplish the compression.

Only heat rejection will reduce the work requirement for the return stroke below the power stroke.

Sorry, but you are an idiot, don't know basic science or understand conservation of energy or the meaning of basic thermodynamic terminology

"Adiabatic" only means there is no heat transfer. Cooling during adiabatic expansion can be the result of both the expansion work itself AND additionally any work the engine is performing; turning the crankshaft, overcoming friction and driving any additional load

All of those work outputs result in additional cooling above and beyond the minimal cooling from gas expansion with zero load, no friction of atmospheric pressure or other resistance.

So your statement above is not true at all.

And in particular "Only heat rejection will reduce the work requirement for the return stroke below the power stroke." Is total BS

You are either ignorant or a liar.