Author Topic: How narrow can the chimney be?  (Read 699 times)

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Offline shuboyje

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Re: How narrow can the chimney be?
« Reply #20 on: March 30, 2014, 10:06:47 PM »
There is nothing more turbulent then requiring the flows to cross.  I've installed many systems where that exact technique is used to mix air.  I do agree the door opening could now be slightly oversized to carry only the combustion air, but that can be addressed pretty easily with a draft door. 

I don't see where this effects the ovens ability to scavenge?  Or do you mean scavenge at the rates you posted earlier?  If so that same thing could probably be said of most ovens... 
-Jeff


Offline stonecutter

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Re: How narrow can the chimney be?
« Reply #21 on: March 30, 2014, 10:08:15 PM »
Thanks, though I don't have an issue with understanding how ovens and masonry function....and that's why I disagree with a flue in side the oven, it makes no sense to me at all.  Heat will escape the oven chamber faster if the flue is in the oven...period.

When you see masonry structures that are vented like that...inside the fire chamber...they are more like fireplaces, masonry heaters or furnaces, not wood ovens for cooking.  I have seen a few vented like that..but they are not efficient.   

And, this is not a that big of a deal to fix, especially since the whole front panel isn't bonded to the rest of the bricks of the enclosure. Take that off, install a hearth..which is nice to have...then it's a couple simple arches or straight chase with an angle iron like what's there now.

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Offline stonecutter

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Re: How narrow can the chimney be?
« Reply #22 on: March 30, 2014, 10:09:15 PM »
There is nothing more turbulent then requiring the flows to cross.  I've installed many systems where that exact technique is used to mix air. 

In masonry ovens?
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When we build, let us think that we build for ever.
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Offline shuboyje

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Re: How narrow can the chimney be?
« Reply #23 on: March 30, 2014, 10:17:31 PM »
In masonry ovens?
Of course not, in large mechanical equipment.  It used to be common to have mixing vanes to create turbulence when you wanted to mix two air flows.  In todays era of cheap you rarely see that in even the highest end equipment and instead the two streams to be mixed are crossed to create turbulence.

-Jeff

Offline Tscarborough

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Re: How narrow can the chimney be?
« Reply #24 on: March 30, 2014, 10:19:15 PM »
In the WFO you do not want the flows to mix, you want a laminar airflow, hot flue gas on top, cool fresh air on bottom.

Offline shuboyje

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Re: How narrow can the chimney be?
« Reply #25 on: March 30, 2014, 10:25:01 PM »
In the WFO you do not want the flows to mix, you want a laminar airflow

I agree, and having them cross each other in the same space with no surface between them leads to turbulence.  Separating the flows would be more conductive to laminar flow, not less. 
-Jeff

Offline stonecutter

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Re: How narrow can the chimney be?
« Reply #26 on: March 30, 2014, 10:29:12 PM »
Of course not, in large mechanical equipment.  It used to be common to have mixing vanes to create turbulence when you wanted to mix two air flows.  In todays era of cheap you rarely see that in even the highest end equipment and instead the two streams to be mixed are crossed to create turbulence.

Then that really doesn't apply to wfo technology, which is simple.  It's funny how complicated it appears to be though, especially in an idealist discussion.


 Today's area of cheap..good one, and very true.  Walmart culture it is....
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When we build, let us think that we build for ever.
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Offline Tscarborough

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Re: How narrow can the chimney be?
« Reply #27 on: March 30, 2014, 10:32:54 PM »
I am not so sure about that Jeff, although you would probably know better than me, I always thought that the best way to produce a laminar flow was to have two masses moving in opposite directions in contact.


 

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