Mv<>mV

[Grimer]

Well, at least you have nailed your flag to the mast. :-)

Well done.

I shall just have to wait for someone who has one of these simple Stirlings to confirm what I say is correct.
There must be somebody on the forum who can do this.

[ovyyus]

Here's a Stirling engine with hot and cold applied at the same time: https://www.youtube.com/watch?v=ABKmm_aBuH0

[Grimer]

Having read up on the Stirling I agree that what I called a counterweight is in fact the power cylinder and my statement about putting the engine horizontal was incorrect.

However, the claim about the engine running backwards still stands.

Your interesting example could be the result of the cold source being much greater than the hot source in which case the cold source will dominate.

I maintain that if you use the hot source alone the engine will turn one way and if you use the cold source alone it will turn the other.

We are getting there - slowly.

[Grimer]

I think I can see why the two directions are different.

With the simple Stirling experiments both the hot and the cold sources are applied to the bottom face.
This means that the heat flow is reversed. For the ice the heat is flowing from the top face to the bottom face.
For the coffee cup the heat is flowing from the bottom face to the top face.

Now why couldn't you have told me that?

It's ovyyus when you think about it, eh! ;-)

[ovyyus]

You don't need me, you got there on your own ;)

[oldNick]

Hi Grimer,

The direction the flywheel turns is dependent on the position of the crank pin at the start.
If it is to the right as in your picture, and you chill the base the air inside will shrink and the power piston will be pulled down,and the flywheel will turn clockwise.

If the crank pin is to the right as shown in your picture, and heat is added to the base the air inside will expand and the power piston will be pushed up, and the flywheel will turn c/clockwise.

Nick

[Grimer]

You don't need me, you got there on your own ;)

Yes, but it was the example you gave that clinched it.

I thought,

"Hang on. The ice is on the top here. In the classic experiments it's on the bottom."

And then things clicked.

It shows the importance of commutation. All we need to do is reverse the direction of torque on one side of the Bessler axle. Trouble with pendulums is one has to find an effective way of coupling them.

[Grimer]

Thanks to understanding the analogy between heat and angular momentum I think I can now see how to achieve a Bessler type wheel.

By "Bessler type" I mean it harnesses gravity by swinging weights and the weights work in pairs.

FunWithGravity2's experiments and my limited experimental follow up taught me the significance of the transfer of action between different sizes of pendulums.

If one has a short pendulum on the driving side and a long pendulum on the other side then all things being equal the short pendulum (analogous to high temperature source) will exert a greater down force on its pivot than the long pendulum (analogous to low temperature sink).

With a suitable coupling one can allow the short active pendulum to lengthen and the long passive pendulum to shorten. This is analogous to the hot source getting colder and the cold sink getting hotter.

In the Stirling example total heat is conserved. Energy arises from the difference in heat intensity being expended.

Likewise in the Bessler type wheel angular momentum is conserved. Energy arises from the difference in the pendulum lengths and periods being used up.

I have found a simple way of coupling different pendulums and an even simpler way of resetting the pendulums, a way which in the limit is energy neutral.

I'll prepare some diagrams tomorrow which will explain matters more clearly.

From what little Trevor has told us I think I might have stumbled on his idea. If so I'm afraid I will raining on his party.

If it should prove to be the same as his idea then I can both understand his unshakable confidence and the problem he's having in practical implementation.

[Grimer]

Grimer, the above diagram looks like it was labelled by someone who doesn't understand Stirling engines.

Quite right, it was, me. :-(

I was trying to force my Stirling into a Keenie Procrustean bed. I can't think what got into me. Probably a touch of the Bessler demon at work.

The label 'counterweight' is actually the power piston.

Indeed.

[/quote]The 'separator/beam' is actually the displacer.[/quote]
Absolutely.

[/quote]There is no pendulum.[/quote]
Correct. But there are oscillators. Fast ones on the hot plate and slow ones on the cold plate.

Interestingly enough Newtonian gravity has its part to play in the operation of the Stirling. Like the Rubber Band Motor the Stirling will not work when laid on its side.

That statement is not correct.

You're being too polite. It's absolute bollocks.

Gravity serves no primary role in the function of a Stirling engine.

Couldn't agree more - now.

In fact, just for fun, I froze my Stirling to a tin full of ice (see image below) and held the Stirling sideways. It continued to rotate quite happily.



I even went further and held it upside down when, again, it continued to rotate.

Thanks very much for bringing me back to the straight and narrow path which leads to salvation, Bill.

It just goes to show that one gains enormously by bring one's ideas out into the open and not being analy retentive.

[ovyyus]

Correct. But there are oscillators. Fast ones on the hot plate and slow ones on the cold plate.

Not just on the hot & cold plates, everywhere around us. All is in 'perpetual motion'.

If Bessler somehow managed to harness all these fast and slow oscillators (heat) then his wheel was a heat engine. As with any heat engine, gravity would not be fundamental to Bessler's principle of operation - even though he applied that principle to drive a gravity wheel. Allowing gravity to assume centre stage was a guiltless deception.

[Grimer]

Correct. But there are oscillators. Fast ones on the hot plate and slow ones on the cold plate.

Not just on the hot & cold plates, everywhere around us. All is in 'perpetual motion'.

If Bessler somehow managed to harness all these fast and slow oscillators (heat) then his wheel was a heat engine. As with any heat engine, gravity would not be fundamental to Bessler's principle of operation - even though he applied that principle to drive a gravity wheel. Allowing gravity to assume centre stage was a guiltless deception.

Can't agree.

Short and long pendulums are oscillators which are driven by gravity.
One may think of a short pendulum as a macro cold particle and a long pendulum as a macro hot particle.

Bessler found out how to transfer "swinging" from the cold to the hot particle and how to reset the system. I shall be explaining how one can do this in later posts.

Also, as I've already pointed out, the term "Heat Engine" is a misnomer. They are heat difference engines. If you have balanced amount of calories on the hot and cold plates then when all the temperature difference has been used up in producing mechanical work the the amount of calories in the closed system is exactly the same at the end as at the beginning. No calories have been consumed, ergo, no heat has been used.

An accelerating body is not a velocity body, it is a velocity difference body.
The differential of velocity is acceleration, not velocity.

We should really think of heat engines as ectropy/entropy engines for want of a better word(s).

[AB Hammer]

Frank

You need to look at this video.

https://www.youtube.com/watch?v=oKmYqUSDch8

[Grimer]

An interesting heat difference engine but apparently not very efficient.

I suppose it's an example of a solid "working fluid". :-)

[AB Hammer]

Nitinol is an interesting memory metal. A blend of nickle and titanium. In the early days of trying to lighten up armor for our combatants of SCA. Titanium was used only to find all the shaping disappear in about a year, looking more like the tin man off the wizard of Oz. Metal memory is interesting. The nitinol can be the answer to some of our problems for it seems not to be fully explored for its possibilities.

Alan

[Grimer]

"The two most useful properties of the metal are corrosion resistance and the highest strength-to-density ratio of any metallic element.[5] In its unalloyed condition, titanium is as strong as some steels, but less dense."

We learn something new every day. For it to be as strong as steel unalloyed is remarkable.

I suppose being low down in the periodic table it has some fluid type characteristics. Nickel just amplifies that property.