×
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

Temperature difference

Temperature difference

Temperature difference

(OP)
Hello,


I am dealing with thermal expansion for a 32'' Steel pipe that will transport water. Parts of the pipe will be buried and some other exposed. I am very unsure on what to use as dT when calculaten the stress created by thermal expansion. Is is the largest difference in ambient temperature for the area, or the difference between operating temperature and ambient temperature? May something completely different I am not sure. BTW I am trying to calculate linear expansion not radial. Please help!

Sorry for the bad english

RE: Temperature difference

You should use the difference between tie-in temperature and maximum temperature, or tie-in temperature and minimum pipe temperature. Max - tie-in will give you the highest axial compressive stress (usually the worst case, because of the combined stress result of "adding" compression with hoop tension stress). Tie-in - Minimum Temperature will give you the maximum axial tension stress.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

RE: Temperature difference

(OP)
Thank you very much for your answer. I can't find the definition of tie-in temperature online would you please elaborate on that?

RE: Temperature difference

It's the ambient temperature at the time when you weld the strings together. Once welded in at that temperature there will be no thermal stress, so it is the "reference temperature" for all thermal stresses developing thereafter.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

RE: Temperature difference

Tpolleri,

You need to use the difference between the the pipe temperature at the time of installation (normally 10 or 15 deg.C) and the warmest or coldest pipe operating temperature.

The idea is to calculate the maximum thermal expansion/contraction of the pipe after installation. Hence, dT= (pipe temp. at the time of installation)-(warmest or coldest metal temp.)

RE: Temperature difference

(OP)
Thanks everyone for their answers I really appreciate all the help.

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