# Pipe diameter expansion due to temperature increase

## Main Question or Discussion Point

Hi

Firstly, this is not a homework problem. It's regarding some flow experimental results I have and to understand the results further I am trying to identify possible reasons for the patterns I see. I don't have expertise in thermodynamics hence finding the following problem a bit puzzling. Any help and pointers would be most appreciated.

I have a 60mm OD stainless steel pipe with a wall thickness of 2.5mm I'd like to calculate the increase in both these values as the temperature of water within the pipe increases by 10 deg C. The straight length of the pipe is 4m and it is part of a complicated flow loop so therefore some approximations will need to be made.

How would I go about calculating the increase in the pipe OD and wall thickness as a result this change in temperature? Thanks in advance for your help!

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russ_watters
Mentor
It is a straightforward calculation multiplying coefficent of thermal expansion by length (of whatever dimension) and temperature change. Give it a try and we'll check your answers...

It is a straightforward calculation multiplying coefficent of thermal expansion by length (of whatever dimension) and temperature change. Give it a try and we'll check your answers...
Thanks for your reply! Why should the length of the pipe matter when I am after the expansion in diameter of the pipe? Did you mean diameter instead of length? Puzzled but I'll have a go assuming that you meant to say diameter. Forgive me for being dim! :(

thermal expansion=6.5e-6 (for stainless steel)
temp change= 50F
D=60mm (0.197ft)

So

expansion= 6.5e-6 x 0.197 x 50= 0.06ft ~ 18mm?

That sounds horribly wrong. I think I've misunderstood what you've said. Any help will be much appreciated!

P.S: Could you recommend a reputable book which has changes in pipe diameter as a result of varying temperature?

Mapes
Homework Helper
Gold Member
Why should the length of the pipe matter when I am after the expansion in diameter of the pipe? Did you mean diameter instead of length?
The diameter is also a length (as is the radius, wall thickness, etc.). They all have units of distance, and they'll all expand linearly with temperature if unconstrained. It's just a confusing part of the terminology that the word is the same as the word that describes the distance of the longest extent of the pipe (the pipe length).

expansion= 6.5e-6 x 0.197 x 50= 0.06ft ~ 18mm?
Whoa, check your calculations. How can multiplying a number in the parts per million by ten give you 0.06?

P.S: Could you recommend a reputable book which has changes in pipe diameter as a result of varying temperature?
It's not a book, but http://www.engineeringtoolbox.com/thermal-expansion-pipes-d_283.html" [Broken] might get you started.

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