Static Pressure Increase Due to Thermal Expansion
Static Pressure Increase Due to Thermal Expansion
(OP)
I had a rupture disk fail due to thermal expansion in a 6" dia CS aboveground pipeline. How can I determine the pressure increase?
Thanks.
Thanks.





RE: Static Pressure Increase Due to Thermal Expansion
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Static Pressure Increase Due to Thermal Expansion
RE: Static Pressure Increase Due to Thermal Expansion
find the CTE (cubic) for the fluid, multiply by the appropriate temperature differential to find change in fluid volume with no pressure change. Call this DVF.
Find the CTE for the pipe material, multiply by temp. difference, cube the result - this is the change in volume of the pipe with no pressure diff., call it DVP.
Calculate the dVol/dpressure for the pipe - requires knowledge of pipe stress equations. Call this factor DVDPP.
Calculate the dVol/dpressure for the fluid - this is also known as the fluid's bulk modulus. Call it DVDPF
The pressure is the common factor here, i.e. Ppipe = Pfluid.
So, calculate the pressure rise, plug it into the pipe equations to find the volume expansion of the pipe, subtract that number from the volume expansion of the fluid, and recompute the pressure rise in the fluid, use the new pressure to recalculate the pipe expansion....etc.
There is probably an algebraic solution too, but I don't have time to work it out for you.
RE: Static Pressure Increase Due to Thermal Expansion
Thanks for your help.
RE: Static Pressure Increase Due to Thermal Expansion
RE: Static Pressure Increase Due to Thermal Expansion
There is a note in an old Crane Valve catalog no. 60 page 14 about tests with 33 API fuel oil in a closed filled vessel. Two tests run from 76 deg F and then 82 deg F start to a 95 deg F final / 113 deg F final, showed a linear rise in pressures. The 113 deg F final temperature resulted in a final pressure over 2500 psi (250 psi initial = 2250 psi rise), while the second test to 95 deg F resulted in final pressure 1575 psi (150 psi initial = 1425 psi rise). So the pressure increased by 73 to 75 psi / deg F.
Crane Valve Co was trying to make point about pressures in a bonnet cavity of a shut-in gate valve. The same could be said for pipeline without any expansion bottles or vapor pockets. Crane Valve chart of tests has the title of 'Thermo-Piezo Effects of Oil at Constant Volume'.
Your Nps-6 pipe system could have had an increase over 1800 psi if the rupture disk did not open. The Nps-6 pipe Sch40 rating might be 1300 psig except for flanges or valves.
RE: Static Pressure Increase Due to Thermal Expansion
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Static Pressure Increase Due to Thermal Expansion
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Static Pressure Increase Due to Thermal Expansion
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RE: Static Pressure Increase Due to Thermal Expansion
Regards,
athomas236
RE: Static Pressure Increase Due to Thermal Expansion