Gary Buster wrote:

Well, now you guys have gone and made me do it.... I just sent the

drawings to Mark

Sedickas in Wa. to weld up an inconel exhaust manifold for the ported 12a...

He will make one of his famous tangential collector tubes and then I will

clamp a

Stainless Steel flexpipe to the rest of the existing system.

The drawings went in today's mail... we'll time the return of the finished

product

to detemine his proficiency... BTW, he does this on his off hours!!!!

On another interesting note, he is wanting to experiment with putting some

"vortex

generator vanes" inside the tangent pipe to disrupt the swirling and

effect a

faster educt into the rest of the system.  I am looking forward to seeing

how this

will turn out!!!

I'll keep you informed regarding the progress, costs, and performances!!

Jeff Spitzer wrote:

There is considerable merit to this idea.  I keep forgetting to warn you
guys about swirl-choke.  That is when a swirling flow reaches sonic
(choked) conditions well before the axial velocity alone.  This tangential
muffler design is a perfect example of how to cause swirl choking.  You
introduce a tangential flow at a fairly large radius and high tangential
speed.  Then as more flow is added and the gases move toward the exit of
the chamber, they are squeezed down toward the center.  Conservation of
angular momentum causes the swirl velocity to go up.  The smaller the
outlet the higher the swirl velocity.  Now, when the vector sum of the
axial velocity required for flow continuity and the swirl velocity equal
mach 1 then the system is choked.  The only way to pass more mass through
the system is to raise the density of the gas which imples greatly
increased back pressure.  If you think this is a non-issue, I doubt it.  My
guess is the swirling is pretty intense and only a few hundred feet per sec
feeding-in is all it takes.  This phenomenon is well documented and is used
on some small gas turbines as an automatic governor.  The flow leaving the
turbine has residual swirl on purpose.  If the swirl goes up (due to excess
flow through the turbine) the thing chokes and increases the back pressure
thus limiting the flow.  Beware.

Jeff Spitzer

 
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