What a difference a flue makes! +75%

Discussion on Stirling or "hot air" engines (all types)
cbstirling2
Posts: 143
Joined: Sat Dec 17, 2016 9:35 pm

What a difference a flue makes! +75%

Post by 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.



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

Attachments
image.jpg
image.jpg (26.92 KiB) Viewed 4085 times
CBStirling2

cbstirling2
Posts: 143
Joined: Sat Dec 17, 2016 9:35 pm

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

Post by 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.
image.jpg
image.jpg (105.72 KiB) Viewed 4084 times
Notice there is insulation at the top of the cold cylinder to insulate the regenerator.
image.jpg
image.jpg (106.22 KiB) Viewed 4084 times
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
Posts: 2137
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Post by 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: 143
Joined: Sat Dec 17, 2016 9:35 pm

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

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

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

Post by 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: 2137
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Post by 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: 143
Joined: Sat Dec 17, 2016 9:35 pm

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

Post by 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: 2137
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Post by 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%

Post by 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
Posts: 10
Joined: Wed Feb 08, 2017 12:33 pm

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

Post by 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: 2137
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Post by 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
007 (640x480).jpg
007 (640x480).jpg (185.1 KiB) Viewed 4013 times

harry56
Posts: 4
Joined: Thu May 25, 2017 9:46 pm

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

Post by harry56 » Fri May 26, 2017 12:17 am

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


วิธีเล่นบาคาร่า

cbstirling2
Posts: 143
Joined: Sat Dec 17, 2016 9:35 pm

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

Post by cbstirling2 » Sun Dec 03, 2017 8:06 am

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?
CBStirling2

Ian S C
Posts: 2137
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

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

Post by Ian S C » Mon Dec 04, 2017 3:46 am

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
[img]
Test 008 (640x480).jpg
Test 008 (640x480).jpg (185.55 KiB) Viewed 2034 times
[/img]

cbstirling2
Posts: 143
Joined: Sat Dec 17, 2016 9:35 pm

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

Post by cbstirling2 » Mon Dec 04, 2017 7:54 am

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?
CBStirling2

Post Reply