What a difference a flue makes! +75%

Discussion on Stirling or "hot air" engines (all types)
cbstirling2
Posts: 113
Joined: Sat Dec 17, 2016 9:35 pm

What a difference a flue makes! +75%

Postby cbstirling2 » Thu Mar 02, 2017 9:18 pm

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
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CBStirling2

cbstirling2
Posts: 113
Joined: Sat Dec 17, 2016 9:35 pm

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

Postby cbstirling2 » Thu Mar 02, 2017 10:13 pm

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...
CBStirling2

Ian S C
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Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Postby Ian S C » Fri Mar 03, 2017 3:09 am

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

cbstirling2
Posts: 113
Joined: Sat Dec 17, 2016 9:35 pm

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

Postby cbstirling2 » Fri Mar 03, 2017 5:19 am

Just got an email from the other guy. He corrected himself. It's an alpha.
CBStirling2

Aviator168
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Joined: Tue Feb 08, 2011 2:29 pm
Location: Brokeville, NY. USA

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

Postby Aviator168 » Sat Mar 04, 2017 9:04 pm

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.

Ian S C
Posts: 1970
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Location: New Zealand

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

Postby Ian S C » Sun Mar 05, 2017 1:27 am

It also helps that the flame is putting most of it's heat around the hot cap.
Ian S C

cbstirling2
Posts: 113
Joined: Sat Dec 17, 2016 9:35 pm

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

Postby cbstirling2 » Sun Mar 05, 2017 2:21 pm

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
CBStirling2

Ian S C
Posts: 1970
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Postby Ian S C » Mon Mar 06, 2017 1:52 am

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

Aviator168
Posts: 308
Joined: Tue Feb 08, 2011 2:29 pm
Location: Brokeville, NY. USA

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

Postby Aviator168 » Mon Mar 06, 2017 4:06 am

Don't know if you can do this. Use an up-side-down flame. Steam car engines use that scheme.

PetePeterson
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Joined: Wed Feb 08, 2017 12:33 pm

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

Postby PetePeterson » Mon Mar 06, 2017 7:54 am

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

Ian S C
Posts: 1970
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Postby Ian S C » Tue Mar 07, 2017 1:05 am

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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harry56
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Joined: Thu May 25, 2017 9:46 pm

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

Postby harry56 » Fri May 26, 2017 12:17 am

You can have a look at some of my Stirling engine generator progress here:


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