large lamina flow build

[Tom Booth]

I'm thinking in terms of using it to improve the efficiency, rather than being the power source.

Interesting. Though I can form no concept of how that might work.

Can you explain?

Regarding another interesting device. The orifice in the laminar flow Stirling, if it works in some way similar to the ball "levitating" on a jet of water, might have an effect similar to the live steam injector nozzle.

Screenshot_20200627-033153_crop_34_resize_18.jpg (140.17 KiB) Viewed 2942 times

The way this steam injector works still seems miraculous to me, and it is difficult to comprehend but it works.

Steam from the boiler goes out through a pipe and is passed through a nozzle where the high pressure steam increases in velocity. There is a kind of Venturi in the nozzle that sucks in water, the steam condenses and the entrained water and condensed steam go back into the boiler through a check valve.

It works in a closed loop with no moving parts, other than valves.

This seems impossible.

The best explanation of how it works I've ever come across is this:

From another forum:

"...pressure is always inversely proportional to velocity, so if you see a jet of air or water squirting out, you know that the pressure had to have gotten converted to velocity in the nozzle. Furthermore the resulting jet of fluid pushes far out into the stagnant fluid and maintains its form, it doesn't just bunch up in a low pressure blob around the nozzle.

"Think of a jet of fluid as being where all the fluid molecules are pushing in the same direction, whereas in a high pressure fluid the molecules are each pushing in a different random direction. A convergent nozzle forces the molecules to move in a coherent forward direction. You still have the same energy, but now the vectors are all additive"

"The secret is that when the velocity of a fluid increases, the pressure decreases, yet a high-velocity flow always pushes aside stagnant (fluid) even if it is at a higher pressure. Furthermore, a high-pressure flow in a pipe can be accelerated simply by narrowing the pipe."

"There are several demonstrations on the web that show this to be true. Generally, they show how you can balance a ball in a jet of air or water and the fluid flows equally on all sides of it, showing that the pressure of the surrounding air is pushing the ball into the center of the jet."

https://aircaraccess.proboards.com/thre ... tor?page=1

If the orifice in the laminar flow engine is acting as a nozzle "simply by narrowing the pipe" to increase the velocity and coherence of the gas striking the piston, then it is not high pressure driving the piston but rather high velocity.

Be that as it may, theory and speculation aside, the live steam injector works.

By converting pressure to velocity through a nozzle in a laminar flow, a fluid can be accelerated in a way that overcomes the pressure from which the flow originated, so steam pressure converted to a high velocity stream can be used to inject itself, along with additional entrained fluid back from whence it came.

Quite a trick!

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

So, might shaping the orifice in a laminar flow Stirling more like an actual cone or nozzle increase velocity better than a simple straight orifice?

[Sockmonkey]

I'm thinking in terms of using it to improve the efficiency, rather than being the power source.

Interesting. Though I can form no concept of how that might work.

Can you explain?

Regarding another interesting device. The orifice in the laminar flow Stirling, if it works in some way similar to the ball "levitating" on a jet of water, might have an effect similar to the live steam injector nozzle.

Screenshot_20200627-033153_crop_34_resize_18.jpg

The way this steam injector works still seems miraculous to me, and it is difficult to comprehend but it works.

Steam from the boiler goes out through a pipe and is passed through a nozzle where the high pressure steam increases in velocity. There is a kind of Venturi in the nozzle that sucks in water, the steam condenses and the entrained water and condensed steam go back into the boiler through a check valve.

It works in a closed loop with no moving parts, other than valves.

This seems impossible.

The best explanation of how it works I've ever come across is this:

From another forum:

"...pressure is always inversely proportional to velocity, so if you see a jet of air or water squirting out, you know that the pressure had to have gotten converted to velocity in the nozzle. Furthermore the resulting jet of fluid pushes far out into the stagnant fluid and maintains its form, it doesn't just bunch up in a low pressure blob around the nozzle.

"Think of a jet of fluid as being where all the fluid molecules are pushing in the same direction, whereas in a high pressure fluid the molecules are each pushing in a different random direction. A convergent nozzle forces the molecules to move in a coherent forward direction. You still have the same energy, but now the vectors are all additive"

"The secret is that when the velocity of a fluid increases, the pressure decreases, yet a high-velocity flow always pushes aside stagnant (fluid) even if it is at a higher pressure. Furthermore, a high-pressure flow in a pipe can be accelerated simply by narrowing the pipe."

"There are several demonstrations on the web that show this to be true. Generally, they show how you can balance a ball in a jet of air or water and the fluid flows equally on all sides of it, showing that the pressure of the surrounding air is pushing the ball into the center of the jet."

https://aircaraccess.proboards.com/thre ... tor?page=1

If the orifice in the laminar flow engine is acting as a nozzle "simply by narrowing the pipe" to increase the velocity and coherence of the gas striking the piston, then it is not high pressure driving the piston but rather high velocity.

Be that as it may, theory and speculation aside, the live steam injector works.

By converting pressure to velocity through a nozzle in a laminar flow, a fluid can be accelerated in a way that overcomes the pressure from which the flow originated, so steam pressure converted to a high velocity stream can be used to inject itself, along with additional entrained fluid back from whence it came.

Quite a trick!

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

So, might shaping the orifice in a laminar flow Stirling more like an actual cone or nozzle increase velocity better than a simple straight orifice?

Specifically I'm thinking in terms of using it with the Manson cycle because that type takes in a fresh charge of air with each stroke. As the stroke is not infinitely adjustable, efficiency is going to start dropping off a bit at the high end of the power curve. Specifically, the air being exhausted from the cylinder is going to have a good bit of left over heat and pressure. So, you run that exhaust through a vortex tube. Use the cold air for cooling the cold side, and the hot air to help heat the hot side.

The laminar flow nozzle will help with the entrainment, certainly. I'm not sure how much it would help pushing a piston. Generally, a high-speed flow works best with a turbine of some sort. Maybe with a Tesla turbine? Those are pretty easy to make.

[Bumpkin]

I don't know if a nozzle could be made to keep a laminar air charge from mixing in air, but a vortex cannon can. https://en.wikipedia.org/wiki/Air_vortex_cannon
I think the nozzle used in some Thermal Lag engines operates like a vortex cannon, isolating the intake air to the hot end from heating until near the end of the stroke, enhancing the thermal lag and pausing expansion until the power stroke. Or it might all just be magic - who knows?

Bumpkin

[Tom Booth]

I don't know if a nozzle could be made to keep a laminar air charge from mixing in air, but a vortex cannon can. https://en.wikipedia.org/wiki/Air_vortex_cannon
I think the nozzle used in some Thermal Lag engines operates like a vortex cannon, isolating the intake air to the hot end from heating until near the end of the stroke, enhancing the thermal lag and pausing expansion until the power stroke. Or it might all just be magic - who knows?

Bumpkin

Funnily, I spent half the day yesterday just watching vortex cannon video's on YouTube and contemplating this whole subject.

I would agree that most thermal lag (same thing as "laminar flow" isn't it?, Just a different name with a different theory of operation) probably put out something more like a vortex cannon.

But I'm rather strongly conviced a laminar blast to the piston would have more force behind it.

Like, what would be more effective at blowing out a candle? A short "laminar flow" burst of air through pursed lips directly focused on the flame or blowing smoke rings at it?

What if the steel wool regenerator were replaced with something like a piece of catalytic converter or carbon nano-tubes. Not sure what would be ideal or work best, if at all, but something more like the bundle of straws in the water fountains.

Figure-3-Honeycomb-cores-of-catalytic-converters_crop_54_resize_39.jpg (40.52 KiB) Viewed 2931 times

Maybe some of this carbon filter stuff:

https://www.amazon.com/URMAGIC-Activate ... B07YBVHJGG

Something like straws but that can take the heat. That carbon fish filter is cheap enough. Just $5 for like a 4 inch cube.

41vIYnwyh1L._AC_SY400_.jpg (26.14 KiB) Viewed 2931 times

Looks like Amazon turned the link I posted into an advertisement. Interesting trick.

[Sockmonkey]

Like, what would be more effective at blowing out a candle? A short "laminar flow" burst of air through pursed lips directly focused on the flame or blowing smoke rings at it?

We aren't blowing out a candle though. We're pushing a piston in an enclosed chamber. In that situation, pressure is more important than velocity.

[Tom Booth]

Could be. I think in a turbine, a nozzle is used to convert pressure into velocity. Power washers, jet engines, rockets, garden hose nozzles, etc. All, presumably, have reason to convert pressure to velocity I think it might be worth experimenting with.

[Tom Booth]

I'm also, not entirely sure, but on a molecular level, wouldn't individual high velocity molecules striking a piston be just as effective as high pressure?

Pressure is, in Kinetic theory, the average of the speed of the molecules. But pressure is in all directions. Velocity has all the molecules traveling in the same direction.

With "velocity" there is the point just ahead of the flow where pressure is high, everywhere else it is low.

Pressure everywhere is wasted and only represents losses, heat through the cylinder walls.

I think the laminar Stirling appears to work differently than other engines.

Other engines don't have an orifice, laminar has no displacer and most telling, runs without a flywheel. I think something unusual is going on.

Also, and perhaps most important, on the return stroke, pressure has to be eliminated. With a narrow laminar jet striking the piston, a small amount of pressure is focused just on the piston, but might actually be just as much force as generalized pressure, but there would be less unused pressure to have to eliminate when the piston has to turn around and travel the other way.

[Tom Booth]

I ordered some of that honeycomb carbon filter.

Unfortunately, it looks like it may be months before it arrives, if at all. Same with some laminar Stirlings I ordered from eBay.

Usually, in the past, I'd be amazed how fast online orders would arrive. Now, even paying extra doesn't help much, maybe only 2 1/2 instead of 3 months if coming from overseas. Or judging from recent reviews, may never arrive at all.

I can't even visit the American Stirling engine company website. It seems to be infected with some kind of redirect advertising spam or something.

[Tom Booth]

Another way some improvement might be possible IF laminar flow has anything to do with it is; from what I've seen, a thin orifice with a sharp knife-like edge gives the best laminar flow.

I found this discussion which might help explain why:

vFeLm.jpg (232.17 KiB) Viewed 2898 times

https://physics.stackexchange.com/quest ... te-orifice

With a long channel the low pressure zone is inside the channel. I would think a long channel would also cause drag which might create turbulence. With a sharp edges orifice the low pressure zone "floats" out ahead of the jet or air stream and so cannot choke the flow through the orifice.

Something else to experiment with anyway.

[Sockmonkey]

With a pulsating flow, having the channel narrow gradually like that actually chokes it a bit because the airflow gets kind of wedged in, so to speak. No time to sort itself out before the pressure is expended.The early Marconet pulse jets used this. Mufflers on 2-stroke engines exploit this to improve fuel efficiency.

[Tom Booth]

I'm not 100% sure what this is, but it shows, in the first few frames especially, exactly how I would imagine a laminar flow in a laminar flow Stirling.

https://youtu.be/mQ50xamE-O8

[Tom Booth]

Got these two engines from eBay. Only took a couple weeks, that offering has apparently ended so, for some reason eBay won't let me get to the original sale to post a link. There are others selling the same item though.

This is what I got:

IMG_20200718_193515706_resize_1.jpg (65.45 KiB) Viewed 2634 times

I wanted to compare steel wool vs carbon filter based on the laminar flow theory, to see if it makes a difference. This engine looked easy to take apart. And I also wanted something with an electric generator, as I want to see what difference it makes loaded vs no load.

My theory about that is; a Stirling engine should run cooler with a load, if it is converting heat into something else, like electricity, Without some kind of actual load the heat has nowhere to go, no mechanism by which it can be converted to something else. So, without a load, more wast heat would be rejected to the cold end, reducing the temperature difference, reducing torque, possibly causing the engine to overheat and stall due to excess heat build up.

For comparative experiments, high quality is not essential. Having engines that are identical, (except for the variable being tested) as far as possible is.

The belt appears to be nothing but a rubber band, but if it works, it will do.

The carbon filters have still not arrived though.

[Sockmonkey]

I'd cobble together a couple of fireboxes for them so the flame won't be exposed, and so more of the flame will actually be heating the engine.
Seriously, that's a pet peeve of mine.

[Tom Booth]

I completely agree, such a waste of heat with these kind of engines with an open flame.

I had this idea for years, but couldn't figure out any relatively easy way to implement it untill yesterday:

viewtopic.php?f=1&t=2682

[Sockmonkey]

I completely agree, such a waste of heat with these kind of engines with an open flame.

I had this idea for years, but couldn't figure out any relatively easy way to implement it untill yesterday:

viewtopic.php?f=1&t=2682

Heating a metal object that's inside something is no problem. You could just wrap an induction coil around the end of the tube. The coil itself doesn't get hot or have to touch the tube. It will induce a current in the regenerator mesh (assuming it's made of metal) with a magnetic field.

The tube should be metal anyhow. the clear stuff is only really good for display models.