Not familiar with the Chisel or tapered
description, George. I may know it as a “wedge” type?
If the Wedge type, all I can tell you is I did quite a bit of searching trying
to find some technical data on it. The only thing I found was wedge
shapes used in supersonic diffusers to slow air down through use of shock waves
(created by supersonic airflow) for inlet to jet engines. I never
found anything on it regarding sub-sonic flow or for heat exchangers.
Anything that will slow air down, increase the pressure before the core and not
cause a lot of eddies and turbulence will probably cool. But, can’t
really comment on how effective they may be compared to say the “StreamLine
duct”.
Yes, the streamline duct is generally a
bit too long for the size cores we use and our cowl lengths – if you
implement a full streamline duct. That is why I have a small section in
my paper on why a truncated streamline duct might still offer some decent
pressure recovery. Since the streamline duct bell shape is not (or should
not be) larger than your core that end should not pose a problem, unless, of
course, you have your radiator canted/inclined and even then K&W addresses that as well, although my paper
does not.
Ed
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of George Lendich
Sent: Sunday, July 19, 2009 9:41
PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: K&W Stream Duct Explanation
Because of insufficient room under cowl, many are using
the chisel or tapered (my name for it) shaped chamber rather than the bell
shaped. To me, it looks to be, like one side of the bell shaped chamber,
or like squeezing a bell shape down to one side. Have you studied this
approach and do you think it's comparable.
Hi Gang
I came across a abstraction of K&W’s
theory of the Streamline duct that I put together a number of year ago.
While it is my interpretation and therefore subject to error, I have not found
anything in the intervening years that indicates a misunderstanding.
While it is not exactly light reading, I think it is easier to follow than K&W.
In any case, I thought I would make it available to promote
understanding and discussion {:>)) of one approach to cooling our
installations.
This paper targets four topic areas:
- Diffusers In General
- StreamLine Duct
- Importance of Inlet
to Core area ( Ai/AB
ratio)
- Truncation of
StreamLine Duct
Best Regards
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.rotaryaviation.com/Rotorhead%20Truth.htm
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