Re: Flow Elements - Recommendation

From: <V.R.H.P.>
Date: Sun Nov 25 2001 - 23:51:00 EST

Rakesh,
I suppose you are looking for the philosophy behind deciding the straight lenths before and after flow element.
It links to theory of Boundary Layer and Secondary Flows in fluid path. After any bend, there will be secondary flows induced near the pipe wall...it proportionately effects local velocity/pressure of the fluid. Considering the length of pipe required to reach to full velocity of liquid, standard straight lengths ahead of Flow Element are established. For after FE, also staright length is required to reach to full velocity after the Vena Contracta condition at FE.
Hope it clarifies upto some extent.

Macharla
--- saud <saud@bushnak.com> wrote:
> Dear Rakesh
>
> The standard recommended dimensions upstream and
> downstream of a flow
> measuring instrument sensor (paddle wheel type etc.)
> is 10 times the
> diameter of the pipe (D) for upstream and 5 D for
> down stream.
>
> With latest magnetic flow meters, this dimension is
> reduced to 5 D and 2 D
> respectively.
>
> Regards
>
> Saud
> ----- Original Message -----
> From: "RAKESH PATIL" <rpa@epc.ltindia.com>
> To: <PipingDesign@yahoogroups.com>
> Sent: Friday, November 23, 2001 6:15 PM
> Subject: [PipingDesign] Flow Elements
>
>
> > ** High Priority **
> >
> > Can anybody give me the basic criteria behind
> deciding the upstream and
> downstream dimensions between Flow Element and
> connecting Fitting /
> accessories in piping?
> >
> > regards,
> > rakesh
> >
> >
> >
> >
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---

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