×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Flow in Eccentric Annuli

Flow in Eccentric Annuli

Flow in Eccentric Annuli

(OP)
Hi all,

Does anyone know of any correlations to estimate the velocity in the narrow gap area of an eccentric annulus?  I know the velocity is lower in this area and heard that there are simple empirical relations to estimate how much lower the velocity is (probably as a function of inner pipe eccentricity) in relation to concentric annulus values.  I know there are many full analytical solutions for eccentric velocity profiles, but I'm looking for the quick rule of thumb correlation.

Thanks in advance,


Atholl

RE: Flow in Eccentric Annuli

OK, I'll give it a try.  Since flow rate is a function of the cube of the gap and the flow area is a linear function of the gap (for small changes in gap), then I would say that the velocity is a function of the square of the gap (average velocity=flowrate/area).

So if the gap were to be cut in half, I would expect the average velocity to be only 1/4 of the original in that area.

For my answer to work, two assumtions are made:

1) You say the gap is narrow.  With a very narrow gap, the flow can be analyzed as flow between parallel plates.  Figure that the ratio of ID to OD should be at least 0.95.

2) The flow must be laminar.  Look for Reynold's number to be less than 1000 to be safe.

Tom

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources