Re: PSV Tailpipe, 45 Degree Cut?

Pretty good info.

• In PipingDesign@yahoogroups.com, "Tony Paulin" <tony@...> wrote:
  >
  > Additional Comments on Beveled Relief Tail Pipes:
  >
  >
  >
  > Notes in the eng-tips thread mentioned by Paul below give many
  thoughts
  > on the subject:
  >
  >
  >
  > Dr. Hans Bos (author of BOS Fluids) added the following, which I
  thought
  > might be useful, and so wanted to pass along:
  >
  >
  >
  > 1) Organ pipe beveling has a small effect on standing wave
  > frequency and this is figured into the tuning process of the
  pipe/organ.
  >
  > 2) The lateral load component at the tail pipe exit is equal
  to
  > the normal thrust force multiplied by the sine of one half of the
  bevel
  > angle.
  >
  > 3) The lateral load component at the end of a relief tail
  pipe is
  > often introduced to reduce the bending moment on the header. The
  bevel
  > angle is adjusted so that the exhaust thrust force acts along a
  line
  > that passes through the centerline of the manifold or header.
  >
  > 4) Beveled ends break the flow symmetry at the exit,
  disturbing
  > the periodic shedding of stable torus type vortices that
  contribute to
  > noise strength. Rotational symmetry in the diamond shaped shock
  > wave/expansion pattern downstream of the tail pipe, in combination
  with
  > the convection of vortices is considered the origin of the
  screeching
  > noise in jet exhausts.
  >
  >
  >
  > Regards,
  >
  >
  >
  > Tony
  >
  > ________________________________
  >
  > From: PipingDesign@yahoogroups.com
  [mailto:PipingDesign@yahoogroups.com]
  > On Behalf Of Paul Bowers
  > Sent: Friday, February 09, 2007 9:13 PM
  > To: PipingDesign@yahoogroups.com
  > Subject: Re: [PipingDesign] PSV Tailpipe, 45 Degree Cut?
  >
  >
  >
  > Sakarya, Hasim (H) wrote:
  > > Paul,
  > > Could you please comment on to what will happen to the horizontal
  > component of velocity if the pipe end is square cut at 90 degrees.
  > > Thanks and kind regards,
  >
  > I quoted NozzleTwister from
  > http://www.eng-tips.com/viewthread.cfm?qid=156173&page=6
  > <http://portal.mxlogic.com/redir/?
  kXLTs7eecfCQXLTp7e9If6M0nM8BVOmFO-6puo
  > Cjz-
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  >
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  80XOcvYQg2jsOhKvxYY1NJ4SyedFTvKOeshv
  > sdNiHu8Pur>
  >
  > Maybe an image is usegul in order to illustrate exactly what I
  mean:
  >
  > http://www.pipingdesign.com/graphics/psv_45_outlet.jpg
  > <http://portal.mxlogic.com/redir/?FTvKUessovdFTvKOesjoudw0BFbiwhg-
  AycenM
  > z7lysHkNqxAlov5qJPfv
  2aN4TvHFETKOyYUqejtPtfxetiWqbXzz1t5dMsMnhh78T7fc8zy
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  > -Ayc3iWq80Ic1AQg0Dp7HimY0Ph0Mq
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  > u8Pur>
  >
  > In neither of these options do I see a benefit in cutting the end
  of the
  >
  > outlet pipe at an angle, but maybe I'm missing something important.
  >
  > Paul
  >
  >
  >
  >
  >
  > [Non-text portions of this message have been removed]
  >