Stirlingengineforum.com

Tom, I don't think you need to be a believer in Kinetic Theory, or any other specific theory, to see that ultimately, the component molecules of your working fluid push on the power piston individually, though it is always easier to think of them "as a whole". All things being equal (which...

The corollary to that point, is that the hot end will tend to be self-regulating (though maybe not always sufficiently!) - heat transfers faster (apparently) between items that have a large temp difference than a small difference, so if the working fluid starts to heat up, presumably the rate of tra...

Les, The trouble with that description of Adiabatic processes, is twofold: 1. In the real world, and especially in hot-air engines, there is ALWAYS some heat transfer in/out of the walls of the engine. 2. Timing. At low speed, or in step-by-step analysis, all of the working-fluid changes temp/pressu...

If the clay won't settle, I guess you'll just have to dry it like salt?

Tom/Vincent, Interesting thoughts. As ever, the real world proves more complex than any 'model/theory' however one thing to bear in mind here is that there are generally considered to be two entirely separate methods of heat transfer: Conduction (which seems to be what you are talking about above) b...

Helium for example can hardly be liquified by any extreme of external cooling and pressure, yet it can be liquified by this method of having it do work expanding in a cylinder to drive an engine to do external "work". Was that a typo? If the expansion of the gas cools it down far enough t...

The specs available on that site, at least at first glance, are essentially non-existent. I wouldn't touch it with a barge pole, and in any case, what is being advertised is little more than a basic kit - you would have to do a lot of work to adapt it to actually cool anything.

I hadn't heard of a "Jake Brake" before - are they really a thing?
My driving instructor taught me how to use engine-braking, then told me never to use the technique unless necessary, as brakes are somewhat cheaper (and easier) to replace than cylinder linings!

I totally agree that the piston would have to remain "in rhythm" with the displacer, but the 'phase angle' would shift. If it shifted far enough, the engine is going to start to "skip a beat" and/or stop completely. I think you might struggle to find a servo that will run fast en...

Tom, I really don't think it is nit-picking to say that gasses NEVER contract on their own, or that the outward pressure of any gas (by definition) is greater than any inter-molecular forces, or gravitational forces, or dark energy. Besides, surely the whole point of this discussion is to try and pi...

One experiment that I have yet to get around to, is de-coupling the displacer from the power piston, and therefore having two flywheels, one driven by the piston, and driving the load; the other driven by an electric motor and driving the displacer. It seems likely to me, that this would automatical...

Tom, There is no such thing as a vacuum - the word is a useful concept, but in reality there is no such thing as a negative gas pressure. We would be in trouble if there were, as all of Earth's atmosphere would be sucked out into space. All of the demonstrations of a can/bottle/whatever imploding ar...

Tom Booth wrote: ↑Mon Aug 14, 2023 1:50 am no real work is done.

What is your definition of "Work" then?

Classically any movement of a physical object means that work was done.

In your spreadsheet diagram, do the purple sections indicate dead-space?

Tom, The simple point is that we all know that you cannot get power out of a machine without putting energy in. We can all discuss perpetual-motion as part of understanding the operation of a "perfect" Stirling engine, ie one with zero friction, but "free energy" is a whole 'noth...