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Al,
Not tested yet, but have one almost complete for
the single.
The cones are there to stop the sound
waves having a direct line of sight out the rear end, the sound waves will
be going all over the place within the exhaust and I tried to replicate that
with the zig zaggy lines.
There is no restriction as the area around the back
to back cones, is equal to the area of the 2" exhaust
manifold area.
However I do take your point on swirl restriction,
but I don't see a problem as it will swirl out the end, whereas sound waves
travel in a straight line ( I think). Bill
did have me put in a reflector plate opposite the incoming exhaust, but I don't
know if this will interrupt the swirl motion, I suspect it might. The reflector
plate is on the LHS of the parts count - photo attached.
George ( down under)
George;
Nice design.
Has anyone run one of these yet.
My concern with the
tangential muffler is something called ‘swirl flow choking’ – discovered in
connection with a similar attempt with gas turbine exhaust. High
circumferential velocity tends to keep the flow from moving out the end, and
consequent pressure buildup. I don’t know whether it applies to the
pulsed flow, but it might, and your conical restriction toward the outlet
could make it worse.
To avoid that
possibility in my tangential muffler I added internal vanes at a 45 degree
angle opposite the ports, and extended the header pipes into muffler to a
squared end. Disrupts the circumferential flow and helps direct the exhaust
toward the exit.
Your depiction of
the idealized sounds waves going axially; ah-h, well; maybe/maybe
notJ.
Al
G
-----Original
Message-----
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of George Lendich
Sent: Thursday, October 08, 2009 1:14
PM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
Re: Your muffler
There you go matey. All off the
shelf SS cones and tube.
----- Original Message -----
Sent:
Thursday, October 08, 2009 9:32 PM
Subject:
[FlyRotary] Your muffler
Do you have a photo or
drawing available of your muffler design..........I seem
to
remember seeing some design info in the
past but do not know where to find it......
--
Kelly
Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
-------------- Original message from
"George Lendich" <lendich@aanet.com.au>: --------------
> Ed,
> Cones are the GO.
>
> Any bare
edge will take a battering from the heat and shock waves. Cones
>
formed back to back eliminate any edges.
>
> There must be
supporting structure for the cones, I've used 1/4" solid
> round
bar welded into the exhaust skin.
> George (down under)
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