[TheForge] Gas forge burners

[Jerry Frost]

----- Original Message -----
From: <Keporter@aol.com>
To: <theforge@mailman.qth.net>
Sent: Friday, April 09, 2004 10:54 AM
Subject: Re: [TheForge] Gas forge burners


> So, the best kind of
> turbulence is that which does the least to "put the brakes" on forward
motion.
> Spinning the gas/air mixture gives the maximum mixing action for the
minimum >drag.
>


Ah vortices! I love vortices, they're such useful things. <grin>

Bernoulli (I'm not sure why Venturii gets the credit) noted that: gas
flowing smoothly (laminar flow) along a curved surface accelerates and
creates a vacuum between itself and the surface. The vacuum at the interface
greatly reduces friction. Interestingly enough it doesn't seem to matter how
it flows, inside, outside, (over, under) across or along there's a pressure
drop and velocity increase. Flowing across yields a greater effect than
along a curve however so even though gas flowing through a pipe enjoys some
effect, it's not nearly as much as if it were flowing across a pipe.

A vortex inside a pipe or outside one for that matter can cause a strong
vacuum and significant velocity increase, depending on the angle of attack
and initial velocity.

As Mike says a good vortice will do a number of positive things for a
propane burner:

The first thing it does is strengthen the vacuum on the intake end.

Secondly it keeps the air and propane together in the tube longer before
ignition.

Thirdly the low pressure environment makes the air and propane mix better.

A strong vortex unfortunately requires a lot of precision to control. If the
tube has any irregularities the flame will be off center or dance or maybe
do something really interesting.

For an easy example of just how much a vortex will improve flow: Fill a
largish 2 litre clear soda bottle with water, upend it and time how long it
takes to drain. Now, refill it and after you upend it give it a little swirl
to get the water spinning. Just a little, half a flick is plenty and time
it.

The difference is easily visible but putting a clock on it really makes it
real.

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

Meadow Lakes, AK.