How do mechanical engineers calculate expansion and shrinkage of vessel between 2 piers?

[tmgczb]

I am a young civil engineer.
I use following equation:
Expansion or Shrinkage △= ε * L.
Among which, α is the expansion or shrinkage(inches) happening per 100 feet, at a temperature more than 7O°F.
If maximum design temperature is 7O°F, ε=0.

But in China, if maximum temperature of material in vessel is no more than 80℃, thermal load would be ignored.
Here, I just want to inquire how mechanical engineers consider it.

 

[dvd]

One point needs to be fixed, and the other needs to allow for movement. Calculate expansion/contraction away from fixed point.

 

[mk3223]

But in China, if maximum temperature of material in vessel is no more than 80℃, thermal load would be ignored

Not sure if this is a general design rule of the projects in China, but it isn't in the Mechanical Engineering design basis.

 

[Christine74]

Yes, ΔL = L[sub]0[/sub] α (T - T[sub]ambient[/sub]).

Generally speaking we assume that the vessel is perfectly insulated so that we don't have to attempt to account for any heat losses. If the vessel is located outdoors we typically assume the effect of solar heating to be negligible, but in some cases for uninsulated vessels you may need to account for that. If there are potential Process upsets that increase the operating temperature for an extended period of time you may need to account for those as well.

But in general we normally assume that the vessel metal temperature is equal to the temperature of the fluid that it contains.


-Christine

 

[RVAmeche]

dvd is correct.

Generally vessels that get hot have one end fixed and one end slides and the vendor dwg will show who much movement. If it's "low temperature" you may get away with two fixed supports.