1 reply to this topic

[asmsyn]

Dear All, 

 

 i have a system in which liquid is getting trapped in a closed pipe.

I want to calculate the increase in pressure in the pipe because of the increase in fluid volume due to thermal expansion.

Please guide me regarding the same....like what should be the approach..?
which formulae to use?
what should be the basic working philosphy etc.....

Thanks in advance .....

 

[ankur2061]

asmysn,

 

Why do you want to calculate the increase in pressure? Is this an academic exercise? If you ar looking for the installation of a "Thermal Expansion Relief Valve" (TERV) for a thermal expansion due to blocked pipe then the best way is to provide a 3/4" X 1" TERV and forget about it, since 3/4" X 1" valves are generally more than adequate to cater the very small relieving rates due to thermal expansion. No need to do any calculations also.

 

If you are insistent to calculate the the relief flow rate due to thermal expansion then I suggest to refer API STD 521 (ISO 23251) Section 5.14 which deals with hydraulic expansion due to heat input for a blocked-in pipe section.

 

As far as calculating the pressure rise due to hydraulic expansion, I have not heard of any process design engineer do it. It is most likely an exercise for somebody who is doing research on hydraulic expansion due to uncontrolled heat input. 

 

Regards,

Ankur.