×
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

Pressure loss pipe fittings during a laminary flow

Pressure loss pipe fittings during a laminary flow

Pressure loss pipe fittings during a laminary flow

(OP)
Hi,
I have got the following question. With turbulent flow fittings have got an almost constant loss factor. It can be found in the literature and internet. Now I am confronted with the question to calculate pressure loss over a fitting with laminary flow. I know that turbulent flow results in a quadratic function ( dP = K*1/2*rho*v^2 ). This goes for the piping itself and the fittings. With laminary flow though the relationship between pressure loss and flow velocity is linear. I assume that the fittings in this case will also behave as a linear resistance. Where can I find the bygoing constants?  

RE: Pressure loss pipe fittings during a laminary flow

I would just take f=64/Re, use Darcy-Wiesbach and call it a day.

Regards,

SNORGY.

RE: Pressure loss pipe fittings during a laminary flow

If you search here for the 2-K and 3-K methods by Hooper and Darby respectively you will find what you need.  You are correct that while the K factors for fittings can be regarded as constant for turbulent flow with reasonable accuracy, the K factors are very different for laminar flow.  However, the equivalent length values (i.e. Le/D) obtained for fittings in turbulent flow can be used for laminar flow.  Using Le/D values will generally estimate slightly higher pressure drops than the 2-K and 3-K methods.

Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com

RE: Pressure loss pipe fittings during a laminary flow

K factors of fittings in laminar flow usually take the form of a constant divided by the Reynolds number, i.e. K = A/NRe.  The slower the flow the larger the K.

Good luck,
Latexman

RE: Pressure loss pipe fittings during a laminary flow

RE: Pressure loss pipe fittings during a laminary flow

(OP)
L.S.,

Thank you for your swift reactions to my questions. I will dig in deeper along the suggestions being made.

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