vertical lamina flow engine?

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Twinsquirrel

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Hi all,

Just wondering if anyone has seen or had experience running/building a lamina flow engine but mounting it vertically and heating the bottom of the regenerator cylinder.

I'm pretty sure it would work but I'm a bit worried about the heat making it's way up the cylinder and reducing efficiency or stopping it running.

cheers

David
 
I don't think it will work? But then again, I don't think a horizontal Lamina will work ether LOL :eek:) Try it and see. Make sure you take pictures.

Wes
 
Powder keg said:
I don't think it will work? But then again, I don't think a horizontal Lamina will work ether LOL :eek:)

hmmm.. I know what you mean, I not sure that I am fully conversant with the theory of these and certainly have no understanding of the numbers involved but I rather fancy building one. I guess I should set up some kind of test rig to do a bit of trial and error and go from there.

David
 
Build a horizontal version and try running it vertical?

Wes
 
Here is a nice link on this topic:
[ame=http://www.youtube.com/watch?v=0-PlT1yFQZ0]http://www.youtube.com/watch?v=0-PlT1yFQZ0[/ame]
 
superb...that's almost exactly what I had planned, hadn't thought of the pendulum though.....nice touch
 
Update,

I've been running a few experiments and for the life of me I can't get a lamina flow to run vertically, to be honest the rig I built would only just run horizontally. Sorry no pics, I've managed to break every single one of my stock of test tubes trying to cut them to tune the length :-\ :-\

I went back and looked at the video you posted Palmrunner and I have a feeling that what is shown is not actually a lamina flow but a thermal lag engine as shown on the stirling engine society webpage, they don't show any working engines but have got a copy of the patent application here: http://www.stirlingengines.org.uk/thermo/tailer.pdf

What do you think?
 
What!!! No Pictures??????????????
rulez.gif
knuppel2.gif


Hope your having fun:)

Wesley
 
I've just been having a browse at the other video's on YouTube from the same source, very nice workmanship 8) ............ in fact ...... you could add quite another few "very's" ;)

CC
 
I thought they were the same type of engine?

Wes, I thought so too, but according to the stirling engine societies' web page they are not, the only difference I can see is that the "regenerator" stack occupies the entire hot cylinder on a thermal lag engine and there are definitely not any thermoacoustics going on?

I've just been having a browse at the other video's on YouTube from the same source, very nice workmanship Cool ............ in fact ...... you could add quite another few "very's" Wink

CC, I've just been doing the same he seems to have done every single type of stirling and they are all stunning
 
To my understanding Lamina and thermal lag engine are both the same type. Thermo-acoustic is something different. Actually there are no videos of thermo-acoustic engines in YouTube. All are Lamina/Thermal lag type, but some builders or sellers prefer to call their engines thermo-acoustic, just because the name sounds more “scientifically” or can be sold better. There is indeed very close visual similarities to a kit sold as “acoustic laser”, where perhaps the confusion comes from. Lamina is able to run in a free piston mode too (without flywheel). This fact makes some believing that a resonance of acoustic waves is what moves the piston. Actually the resonance is defined only by the piston mass and the air spring and the frequency is much lower than the natural resonance frequency of a test tube with this size.
Anyway, the biggest difference between horizontal and vertical Lamina is the place where you apply the heat. The best is to apply the flame just on the border steel wool / air. In a vertical Lamina the flame is applied on the bottom of the test tube, which is the other end of the steel wool. In this way much less heat reaches the right place and Lamina is much less efficient. One way to enable Lamina working at lower temperatures is reducing the compression ratio. I would try shorter test tube (to bring both regenerator ends closer) with larger diameter (to reduce the compression). Shorter piston stroke and reduced opening of the orifice may also help. Keep in mind that Lamina will work with less rpm and less power, so you have to pay special attention to minimize all frictions.

I am currently playing with measuring the shaft power of my Lamina. It could reach almost 200mW for short moment and then the cold side gets warm and the power goes down to around (130-140)mW. From this I was able to extract maximum 80mW of electrical power (8V @ 10mA). This is enough to light 3 white super bright LEDs. I think it can even power a pocket radio.
Unfortunately Lamina is a desperately inefficient engine. Assuming that a small alcohol burner delivers ~40W (if not even more) and the top power of Lamina is 0.2W, we get only 0.5% efficiency, which is quite discouraging result. Despite the facts, Lamina remains the most simple power producing engine.
 
Thanks for the useful info PalmRunner. Your engine in your avatar looks fantastic, even better if it can actually power something other than itself! Is that a ball bearing used as a flywheel? Does the inner race turn at a different rate to the outer?

Nick
 
Yes, the flywheel is made of a large 90mm ball bearing. The outer ring is simply blocked to the inner, so both are running together. I don't own a lathe, so I couldn't find better "flywheel". A bearing flywheel has the advantage that it is relatively accurate (balanced), which matters at speeds >2000rpm. It is heavy enough (~200 gram), as the weight is distributed around the periphery, so it has big momentum.
 
You've done superbly well to make that without a lathe! Good innovation with the flywheel, good point about being balanced, my flywheel is unfortunately not running true, mainly because I rushed it.
 
I'm just about ready now to start making a presentable vertical lamina engine, I've done all the testng I can and now have a running, if embarassingly ugly and very tempremental, test engine. No pictures, it's just too ugly :eek:.

It will probably look quite similar to the one posted earlier in this thread, perhaps not as beautifully made though :-\

Going to make a start on the base and stand today will post progress pics soon either here or in a new thread, wish me luck!

David

EDIT: Forgot to say thank you to Palmrunner, the info you posted earlier was invaluable :bow:
 
David,

Sounds excellent, you should post pics of your experimental setup as it may give other people ideas! Also, at least we might have something to take the mick out of until you finish your 'presentable' version, which if your LTD was something to go by, will make a lot of people very envious! ;)

Good luck, I will be following your thread with great interest!

Nick
 
NickG said:
Sounds excellent, you should post pics of your experimental setup as it may give other people ideas! Also, at least we might have something to take the mick out of until you finish your 'presentable' version,

No really Nick, the experimental version was almost offensive, even my 7 year old boy laughed at it, I couldn't take the shame!!!

David
 

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