Mathematical analysis of dome geometry

[di11on]

Re: Mathematical analysis of dome geometry

Think I'll just copy the dimensions of the Panyol 66 :-)

https://mainewoodheat.com/wood-fired...nyol-model-66/

[GianniFocaccia]

Re: Mathematical analysis of dome geometry

You might build a dome that is optimal for distributing the heat for a particular purpose, but if it doesn't work from an airflow heat generation point of view, you might not get the heat to distribute in the first place???

I believe the 63% golden door-height rule has to be the least-flexible 'variable' in proper dome design. Like StoneCutter said, just look at thousand-year-old ovens to see what good-breathing ovens look like.

According to mklingle's analysis, 42" domes with 21"H and 18"H have virtually identical heat signatures on the floor. Given the intensity of live pizza flames, I'm not sure even a parabolic dome shape would behave any different than a flatter Neapolitan dome.

Although pizza is a main fare at home, I built my oven with a 12" door-height to accommodate taller pots. Working with an 8.5" door-height like the Panyol 66 would certainly come with its own set of challenges.

[stonecutter]

Re: Mathematical analysis of dome geometry

According to mklingle's analysis, 42" domes with 21"H and 18"H have virtually identical heat signatures on the floor. Given the intensity of live pizza flames, I'm not sure even a parabolic dome shape would behave any different than a flatter Neapolitan dome.

Little temperature variables makes sense when your talking hemispherical domes, but there is no way that a flatter dome or more elliptical shape will perform the same, even at lower temps.

A pound of feathers is the same as a pound of lead, like 1000 degrees is a 1000 degrees in an oven.

But whether through convection or radiant heat, the source of the heat is closer to what is being baked, roasted or cooked in an elliptical (Neapolitian) dome. That will translate into much faster cook times, as far as finished product. So that is something to consider when designing an oven shape.

[Tscarborough]

Re: Mathematical analysis of dome geometry

Wood fired ovens do not cook by air temp, they cook via conductive heat (the floor) and radiant heat (the walls, ceiling, and active fire). Radiant heat is squared by the distance, so it has to be balanced with the conductive properties of the floor. Italian ovens using volcanic based materials have very different properties than medium or low duty firebrick floors, thus the ceiling height will be different for an oven using them. The Pompeii oven is not a Neapolitan oven, and the dimensions are different as is the shape of the dome.

All of that is splitting of very fine hairs in reality, but the 62% ratio applies across the range.

[stonecutter]

Re: Mathematical analysis of dome geometry

To be clear, I was talking about the temperature of the masonry, not the air.

[di11on]

Re: Mathematical analysis of dome geometry

With all that in mind, does anyone have any thoughts on what the optimal shape would be for a 26" oven using a grog based castable?

[jeeppiper]

Re: Mathematical analysis of dome geometry

I read through this thread and I sit back and shake my head...and one word comes to mind: "REALLY????"

Radiant heat from the ccurved ceiling (elliptical, circular, cylindrical, parabolic.)....conductive heat from he floor....there is also a large convective heat component and complex flow patterns that aren't being discussed. Now throw an active fire into the mix....????

This is just my opinion, but rather than trying to boil our wood fired oven designs down to some engineering formula, I think we should all simply marvel in the creativity, ingenuity, and practicality of the ancient ones who developed them in the first place and the FB folks who brought this to the fore-front. RELAX and ENJOY, people!!! Each oven is going to be different....each design is optimum in its own way. When you combine the uniqueness of the oven with the imagination creativity of its chef.....

I've said enough and I hope I didn't offend anyone. Im probably going to get a lot of flack from this one.

[Greenman]

Re: Mathematical analysis of dome geometry

We all look for something of substance to hitch our wagon to when planning and building a project as significant as a WFO. I am no engineer so I was impressed with the theories put forward by those with technical skills but the things that sold me on the Pompeii design was the Golden Ratio, the fact that they have been doing the job for 1000's of years and the apparent success of the design.

Add to that the magic of a flickering fire, the smells of good food and the good company it attracts and that's it for me.

It is the nature of man to complicate the simple things and I am sure that there will be tweaking of design and construction methods for as long as mankind draws breath.

[cobblerdave]

Re: Mathematical analysis of dome geometry

G'day
Third man in!
Yep I like the simplicity of the Forno WFO. Oven door, 63 per cent oven of the internal height, a little less than half the internal width for the door.
If its low dome or high doesn't matter, it breaths and regulates itself.
As for the heat it not like a domestic oven and standard recipes, its more like you take you time to cook things as you like. Too high protect it, to low, no such thing just leave it a little longer.
What's with the radiant heat from a brick/caste oven? Its about as different as possible from that from a microwave as you can get. More forgiving I suppose.
The saying goes "don't over think it" it true with a WFO , it follows the laws of nature so don't muck with the ultimate law...
Regards dave