Forces of attraction and repulsion of gas molecules in a Stirling engine.

[VincentG]

I’m not sure where you all were concerned with gravity, but it certainly plays a role in these engines, or at least can be used to one’s advantage.

Maybe you can expand on what you mean.

In terms of the Lennard-Jones potential, gravity helps pull the particles down and therefore also together so our atmospheric air particles are already being "compressed" or squeezed together before we even begin compressing them in an engine.

I meant that when building a Gamma chamber for the thread "Developing a better Gamma chamber", I observed higher temperature air leaving the chamber when the hot end was at the top, compared to at the bottom or laying on its side. That is with a test port directly in between the hot and cold side. I believe gravity helped the hot and cold air separate more effectively, even with a "valvular displacer".

[Tom Booth]

...So the way I see it is that a cold volume can be tolerated, but should be as small as possible.

Luckily the power piston compresses the gas from a large space to a small space, and combined with high enough pressures in this cold space, the partial heating can be much more effective but still not as good as complete heating.

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I was thinking in terms of Tesla's "cold hole", or a heat pump/heat engine combination.

If you're trying to keep the heat input away from the cold ice/evaporator/liquid nitrogen or whatever "cold hole", the proposition is more tenable if the working fluid in contact with the "cold hole" can be maintained at a cold temperature.

A kind of cold air buffer space to more effectively maintain the cold side of the ∆T.

Heating the entire volume of the working fluid would put the hot working fluid into direct contact with the cold plate resulting in inevitable loss of "waste heat" and gradual destruction of the "cold hole" as it takes in heat.

Keeping the "cold hole" protected or isolated looks like a much more realizable possibility if the hot air molecules are not zipping around in an uncontrollable manner at the speed of light.

If this hot side - cold side thermal separation wants to occur naturally, why fight it?

Screenshot_20241110-201054.jpg (180.84 KiB) Viewed 599 times

[matt brown]

bump

[Fool]

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I think I posted to the wrong thread. Grrrrr.


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[Fool]

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The following was supposed to be here...

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Removing work increases efficiency. Removing "waste heat" reduces efficiency.

Why you favor the latter is a bit of a mystery.

As a scientist, I'm taught to avoid favoritism. I favor neither of that false dichotomy. One of theses days you may just learn why heat rejection, (not a waste), is necessary for an engine to have greater than zero efficiency. Without rejecting heat your engine will have zero work output. This is evident in all the LTD Stirling experiments you have demonstrated, and why I harp on measuring the work output. Not because it will prove Tom or Carnot wrong, neither will happen, but to prove what I suspect, near zero work developed. Near zero heat out means, near zero heat in, and near zero work produced. Heat applied, is not the same as Qh heat absorbed, (You erroneously assume that.).

You still, after 20 years, do not understand simple F=Ma, and W=F∆x=P∆V. Or for an impulse: Work equals the integral of dP•dV. And how they relate to PV=nRT and how that correlates to reality in the engines we work with. You've even been given the slightly more complicated formula for real gasses, yet you completely fail to mention that. You also seem to want to apply the molecular attraction formulas to gas equations, when they clearly apply to liquid and solids or during the transition to liquid. You don't yet understand where and why they have negligible effect, as in our work here on LTD Stirling Engines.

Wow! Look how much I must type, just to show how one single erroneous statement of Tommy's, misleadingly casts an erroneous assumption on my thoughts, as if he knows jack about what I prefer. How would Tommy know what I'm thinking? He wouldn't. ('What I prefer!') What a crackup! Get a life. Grow up. Learn some real science. Stay far away from me.

Hint: What is real science called? Science.
What is, non-real science, an attempt at real science, or pseudoscience, called? Quackery. Those other terms are contradictions. There is no such thing as fake knowledge. It's either knowledge or lies. Memorizing a lie is not learning. Building on memorized lies is not learning.

You either know what I'm thinking, or you are lying about what I'm thinking. The only way you could know what I'm thinking is, if you were me. Guessing is lying.

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[Fool]

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The following was supposed to be here...

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Repulsive molecular forces are limited to overlapping electron clouds, apparently.

I think overlapping electron clouds only happens to solids and liquids. Gasses bounce off the electron clouds, no overlapping. But I don't know how close the molecules get. You are bringing your and my lack of quantum theory, into a discussion of the macroscopic theories of thermo and fluid dynamics. The scientific lecture, presented through YouTube, on that subject should have explained why quantum mechanical effects were negligible for higher level modeling. I guess you didn't get that point from it. It was the main point he was extending. Cheer up, lots of students fail to consider a professors main points, and consistently do poorly on an exam. Those students typically waste their study time on irrelevant side points, like quantum mechanics, in a fluid dynamics class. I've seen it happen, and helps those as peers, fellow students. Study what isn't negligible.

The main point here is that repulsive forces are responsible for bounce. They add nothing to the kinetic energy of the molecule. The attractive forces don't add or subtract anything from the kinetic energy of the gas molecules either. Once a gas, both can be ignored, until the kinetic energy slows enough to be close to the boiling temperature and density. Then size also matters. Phase transition and below.

You keep bringing phase change points into a discussion of engines that operate nowhere near phase changes. Yes for steam power, no for Stirlings. No for gas molecules far away from each other, or even bouncing off from each other. The kinetic theory applies to gasses, not to liquefaction temperatures and densities.

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[Fool]

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The following was supposed to be here...

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Instead of removing "heat" it is better to remove "work".

All Matt was saying was that you can't "remove work".

When a gas expands it does work, work out.

When a gas is compressed it has work done to it, work in.

No other points are possible. Total work out of the gas will be work out minus work in, for a complete cycle. That is from the gasses viewpoint.

Tom, I can tell, from your descriptions here, that all your experiments with gasses and engines have been in an Earth surface atmospheric pressure. You are observing a mixture of inside gas behavior with outside gas behavior. It apparently is confusing you.

I suggest you try some gas and engine experiments inside a vacuum chamber. They are relatively cheap, or can be built from common items, like a pressure cooker and thick, glass, acrylic, or polycarbonate plate and cheap Harbor Freight hand pump vacuum brake bleeder. Understanding what science means by 'gasses always push', 'gasses and hydraulics never suck', will become apparent only after doing some vacuum chamber testing.

https://www.amazon.com/dp/B095YGCQFT/re ... p13NParams

That is only an example. Not necessarily the best deal on vacuum equipment. $150...

Take an all glass syringe, push it in completely. Plug the hole. Put it in the vacuum chamber. How much does it expand? All the way? Less?

Suck up some water. Point it up. Push it all the way in, ejecting all air an water. Leave water in just the tip. Eject all air, no bubbles. Plug the tip. Put it in the chamber to see how much it expands. All the way? Less? Try it with hotter water and syringe.

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[Fool]

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Above the spam.

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[Tom Booth]

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The following was supposed to be here...

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Instead of removing "heat" it is better to remove "work".

All Matt was saying was that you can't "remove work".

When a gas expands it does work, work out.

When a gas is compressed it has work done to it, work in.

No other points are possible. Total work out of the gas will be work out minus work in, for a complete cycle. That is from the gasses viewpoint.

Tom, I can tell, from your descriptions here, that all your experiments with gasses and engines have been in an Earth surface atmospheric pressure. You are observing a mixture of inside gas behavior with outside gas behavior. It apparently is confusing you.

I suggest you try some gas and engine experiments inside a vacuum chamber. They are relatively cheap, or can be built from common items, like a pressure cooker and thick, glass, acrylic, or polycarbonate plate and cheap Harbor Freight hand pump vacuum brake bleeder. Understanding what science means by 'gasses always push', 'gasses and hydraulics never suck', will become apparent only after doing some vacuum chamber testing.

https://www.amazon.com/dp/B095YGCQFT/re ... p13NParams

That is only an example. Not necessarily the best deal on vacuum equipment. $150...

Take an all glass syringe, push it in completely. Plug the hole. Put it in the vacuum chamber. How much does it expand? All the way? Less?

Suck up some water. Point it up. Push it all the way in, ejecting all air an water. Leave water in just the tip. Eject all air, no bubbles. Plug the tip. Put it in the chamber to see how much it expands. All the way? Less? Try it with hotter water and syringe.

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As usual, your ideas for "experiments" are completely ridiculous and nonsensical

You can bump it up until dooms day. Nobody's interested.

[Fool]

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As usual you are denying science.

https://en.m.wikipedia.org/wiki/Dorodango

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[Tom Booth]

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As usual you are denying science.

https://en.m.wikipedia.org/wiki/Dorodango

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No, your garbage you post is hardly science.

[Fool]

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I don't post any garbage. You on the other hand have no mathematics to back up your Carnot bashing, or free energy rants. Just Tom's, magnets theory, or spring theory, or tennis theory, or baseball theory, or pushing a car up the hill getting tired theory. What are you going to concoct next, old obsolete theory? Alchemy? PIU? Your ignorance is only exceeded by your arrogance. Your cognitive dissonance blinds you with rage. You continue to gaslight us, in the face of solid logic and data, refuting much of your theories. You constantly misrepresent classical theory as if someone or something has you by the collar. How can you possibly live with yourself?

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[Tom Booth]

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I don't post any garbage. You on the other hand have no mathematics to back up your Carnot bashing, or free energy rants. Just Tom's, magnets theory, or spring theory, or tennis theory, or baseball theory, or pushing a car up the hill getting tired theory. What are you going to concoct next, old obsolete theory? Alchemy? PIU? Your ignorance is only exceeded by your arrogance. Your cognitive dissonance blinds you with rage. You continue to gaslight us, in the face of solid logic and data, refuting much of your theories. You constantly misrepresent classical theory as if someone or something has you by the collar. How can you possibly live with yourself?

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I think you do a lot of projecting.

https://en.m.wikipedia.org/wiki/Psychol ... projection

Go see a shrink.

[Fool]

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Wow! Tommy can link a old archaic Freudian crap. Here is a quote:

Criticism

Some studies were critical of Freud's theory. Research on social projection supports the existence of a false-consensus effect whereby humans have a broad tendency to believe that others are similar to themselves, and thus "project" their personal traits onto others.[37]

Talking about your projections. Sheesh!

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[Tom Booth]

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Wow! Tommy can link a old archaic Freudian crap. Here is a quote:

Criticism

Some studies were critical of Freud's theory. Research on social projection supports the existence of a false-consensus effect whereby humans have a broad tendency to believe that others are similar to themselves, and thus "project" their personal traits onto others.[37]

Talking about your projections. Sheesh!

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Well, I don't know about you but I'm not "blinded with rage".

Your like a running joke.