How to calculate Lateral & Axial Pipes dilatation due thermal exp?

[drakkkko]

What is the formula to calculate Lateral & Axial dilatation , due thermal expansion for the followings: SS, HDPE & FRP pipes.

I Know there is a gral formula for Axial dilatation which is:

Axial Dilatation [mm]= Pipe Length[mm] * Thermal Coeff[mm/mm°C]*(T2-T1) [°C].

But I don't know if apply for all material and I don't know a formula por lateral dilatation.

Thanks in advance for your help!

 

[ColonelSanders83]

The thermal growth formula is always valid for any material when using the proper coefficient of thermal expansion. Last time I checked all materials grow and shrink to varying degrees with change in temperature.

As far as lateral dialation or "Radial Thermal Growth", it can be calculated the same way by subsituting pipe diameter or radius (depending on what portion of growth you care about) for pipe length. Realisticly speaking it is not generally a concern unless you have vary large diameter, stiff (steel or other metal) lines attached to sesitive rotating equipment (like a turbine, a pump or a large thin wall vessel).

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http://www.ap-dynamics.ab.ca/

 

[moon161]

Well, thermal expansion of metals is the same in all directions, and linear.

Plastics may be isotropic, may not be linear.

FRP should be linear, often not isotropic.
I know enough about composites to get in trouble, there are 1 or 2 people writing books on composites here, I'd dig up one of them on this.


In the absence of any constraint, it should be like scaling up a drawing very slightly.

The linear expansion of a curved surface (the pipe wall) should be related to the enclosed diameter by a factor of 1/pi, which is temperature invariant.

The new ID is what you're after, so for the linear isotropic case:

ID2=ID1*TCE(T2-T1)

 

[BigInch]

Thermal area expansion is Area * 2 [α] * dT, volumetric expansion is Volume * 3 [α] * dT

Unless you are calculating shrunk or expanded volumes of gasoline or crude for prices defined at STP, or calibrating meter provers, it is unusual to have to consider anything other than linear (axial or the occasional radius) expansion in any pipe related work.

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