[TheForge] Burner "flares"?

[Jerry Frost]

Cool, you've answered your own questions. I like that. <grin>

However,  your real question is one of those simple sounding ones that tends
to be a can of worms. I believe you're right on the money though. My
opinions are based on a limited knowledge (dangerous at best) a little
experimentation some observation, some speculation and a few working
burners.

Propane and air do not mix well. This I know as I've been told so by a
number of professionals who deal with propane fired devices for a living.

In a linear inducer the air enters in a reasonably laminar flow, is drawn
past the jet and driven down the tube in a fairly smooth manner. This
doesn't mix the gasses very well so you end up with BTU outputs well below
optimum for the fuel consumption.

In a jet ejector the air enters at 90* to the tube and jet from one or more
intake ports and enters under a draw at least 30% stronger. This results in
a more violent mixing action and a hotter, more economical flame. Also, as
the jet ejector induces at a much higher ratio you need to choke the intake
or run WAY lean. This results in the propane and air meeting in a partial
vacuum further improving the mixing.

This trait of propane and air mixing poorly is what makes me believe the
trend of operating at as low a propane gage pressure as possible is a
mistake. You want as strong a mixing action as possible WITHOUT creating the
wrong kind of turbulence. A large, low pressure jet can easily provide
enough draw to induce air but it's a gentle action (quiet) and gentle
doesn't mix gasses well. A small, high pressure jet provides plenty of
propane and induces plenty of air but much more violently (loudly) and mixes
it more efficiently. Better mixing = hotter more efficient fire.

Of course that's just my opinion and I could be wrong. <grin>

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks


----- Original Message -----
From: "Rick & Kims Email" <korineks@rcn.com>
To: <theforge@mailman.qth.net>
Sent: Saturday, April 27, 2002 5:23 AM
Subject: Re: [TheForge] Burner "flares"?


> Jerry,
> Thanks for all the info you provided in your posting about burners,
> etc.
>
> One question that comes to mind about  the "jet burners"...
>
> If it is true that they introduce substantially more air than required
> for a stochiometric or neutral burn w/propane, wouldn't they create a
> oxy-rich or reducing condition in the forge?
>

Oxy-rich = lean or oxidizing flame.

Fuel-rich = rich, reducing or carburizing flame

> OK, that's the reason for the choke sleaves on the burners, to limit
> the amount of combustion air induced.
>
> So, w/a jet inducer burner w/a choke sleave properly adjusted for a
> neutral burn, why is the flame so much hotter than the straight
> burner?  Is it because the jet inducer creates more turbulance at the
> venturi and the result is better mixing of the fuel and air and more
> complete combustion in a smaller space?
>
> I guess there is more than one question here.
>
> Rick Korinek
> Emerald City Forge
> Framingham, MA