Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
(OP)
We have a blocked in liquid scenario between two isolation valves and the medium is water. In our case the temperature is rising from 20°C to 110°C.
My issue with the formula {5.14.4.1-d-(3)} is the variability of the following three variables with respect to pressure and temperature.
αv {is the cubic expansion coefficient of the liquid, expressed in 1/°C (1/°F)}
αl {is the linear expansion coefficient of metal wall, expressed in 1/°C (1/°F)}
χ {is the isothermal compressibility coefficient of the liquid, expressed in 1/kPa (1/psi)}
How should I account for the above 3 variables' variability in the formula? Any input or help would be greatly appreciated!
My issue with the formula {5.14.4.1-d-(3)} is the variability of the following three variables with respect to pressure and temperature.
αv {is the cubic expansion coefficient of the liquid, expressed in 1/°C (1/°F)}
αl {is the linear expansion coefficient of metal wall, expressed in 1/°C (1/°F)}
χ {is the isothermal compressibility coefficient of the liquid, expressed in 1/kPa (1/psi)}
How should I account for the above 3 variables' variability in the formula? Any input or help would be greatly appreciated!





RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
We want to stay away from an RV for now, as installing an RV will be a lot of work in a nuke facility such as ours. We want to analyze as much as we can before we throw in the towel and go with an RV.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
You will find in API 520 (2008) p. 34 equation (3), the calculation for pressure. The several times I have checked for different fluids, the pressure has far exceeded the design pressure of the piping - pressure simply rises quickly as temperature increases. You didn't say if you were protecting piping or a vessel, but the same logic would apply to the latter.
If you are discharging to atmosphere, then you will encounter flashing flow in the discharge piping (relief temp = 110°C). You will want to consider in your piping calculations.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
However the volume involved is very small - some sort of closed volume expansion vessel will take care of 90% of that pressure rise. If the volume in the pipe isn't very big, then neither will be the expansion vessel.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
Just to think about alternatives:
Can you install a bypass check valve arround one gate?
Can you drill one of the two or more gates?
RE: Hydraulic expansion - blocked in liquid (water) scenario - API Clause 5.14.4.
Also, when one gets a resultant pressure of say 13,000 psig for the blocked in liquid what code stress limits are used for the evaluation of the piping and the associated fittings/valves? Is it the normal stress limits or are you allowed to flirt with the yield/tensile stresses of the applicable materials?