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What a difference a flue makes! +75%

Posted: Thu Mar 02, 2017 9:18 pm
by cbstirling2
What a difference a flue makes! This YouTube video shows the power from no flue, to a square one, to a smooth flowing flue. The power went from .37 watts to .44 watts to the highest .65 watts, a 75% increase in power.

http://youtu.be/-8G4GgryJZQ

The engine is an alpha with Ross linkage. Appears to be of high precision.
Thoughts on its construction?

https://youtu.be/mUzz2pPw2Pg

Re: What a difference a regenerator makes! +100%

Posted: Thu Mar 02, 2017 10:13 pm
by cbstirling2
The second video shows the difference a regenerator makes. Doubled the power.

In this, one can see the grooves inside the hot cylinder.
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Notice there is insulation at the top of the cold cylinder to insulate the regenerator.

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http://global.rakuten.com/en/store/over ... -se-905hp/

One guy said this is a gamma engine, but from I've been reading, I'd say its clearly an alpha...

Re: What a difference a flue makes! +75%

Posted: Fri Mar 03, 2017 3:09 am
by Ian S C
Does it have two fitted pistons, one hot, the other cold, the hot one should have a cap on it similar sort of construction to a hollow displacer.
From the pictures at the beginning of the first vid I'd say you are right it's an ALPHA motor.
Ian S C

Re: What a difference a flue makes! +75%

Posted: Fri Mar 03, 2017 5:19 am
by cbstirling2
Just got an email from the other guy. He corrected himself. It's an alpha.

Re: What a difference a flue makes! +75%

Posted: Sat Mar 04, 2017 9:04 pm
by Aviator168
Yes. The flue increases the velocity of the hot air which increase the Reynolds number which increase the effective thermal transfer capability per unit area.

Re: What a difference a flue makes! +75%

Posted: Sun Mar 05, 2017 1:27 am
by Ian S C
It also helps that the flame is putting most of it's heat around the hot cap.
Ian S C

Re: What a difference a flue makes! +75%

Posted: Sun Mar 05, 2017 2:21 pm
by cbstirling2
Aviator and Ian,

So the flue improves the combustion and heat transfer. I wonder how much was the power improved due to increased fuel consumption and how much due to increased heat transfer?

Aviator, many thanks for introducing:
https://en.wikipedia.org/wiki/Reynolds_ ... Derivation

Re: What a difference a flue makes! +75%

Posted: Mon Mar 06, 2017 1:52 am
by Ian S C
It's good if you can line the furnace with something that will reflect the heat inward toward the hotcap, you used to be able to use a sheet of asbestos, but that's a no no these days.
Ian S C

Re: What a difference a flue makes! +75%

Posted: Mon Mar 06, 2017 4:06 am
by Aviator168
Don't know if you can do this. Use an up-side-down flame. Steam car engines use that scheme.

Re: What a difference a flue makes! +75%

Posted: Mon Mar 06, 2017 7:54 am
by PetePeterson
Ian, have you ever checked this out? ITC-100 it is for use in foundry work.
I first read about it after seeing a foundry made from a plastic 5 gallon bucket lined with Kaowool and then coated with
ITC-100 and then ITC-296A. Now they even have a primer for metal.

http://secure.anvilfire.com/itc-ceramic-coatings.html

---
Pete

Re: What a difference a flue makes! +75%

Posted: Tue Mar 07, 2017 1:05 am
by Ian S C
Pete, no I have not, must do some work on furnace design.
I tend to build quite a few vertical motors with the gas burner in the form of a ring around the top of the hot cap. Ian S C
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Re: What a difference a flue makes! +75%

Posted: Fri May 26, 2017 12:17 am
by harry56
You can have a look at some of my Stirling engine generator progress here:


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Re: What a difference a flue makes! +75%

Posted: Sun Dec 03, 2017 8:06 am
by cbstirling2
A guy is selling these things on eBay. It was a long wait to convince my wife. But I finally got the Japanese Ross linkage engine. I'm very impressed with the power. It produces enough electricity to run a 6 volt motor with 100 milliamps on 90 pct alcohol.

Probably the most powerful of my stirling engine so far.
One thing that I did notice is that it vibrates a lot. Do Ross linkage engines require a lot of balancing?

Re: What a difference a flue makes! +75%

Posted: Mon Dec 04, 2017 3:46 am
by Ian S C
My Ross Yoke motor is not too bad as far as vibration goes, but Andy Ross devised a balance system for his motors which consisted of a counter rotating shaft, there is a bit about it in his book "Making Stirling Engines" (free down load on the internet).
Ian S C
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Re: What a difference a flue makes! +75%

Posted: Mon Dec 04, 2017 7:54 am
by cbstirling2
Ian, from your alpha how many watts of electrical power are you able to generate?
What's the bore and stroke?
And it looks like you built it to be pressurized. How much does that increase the power by which pressure?