PSV reaction forces for two phase flow with PRODE

[mpor]

I have to size several PSV for two phase flow case,
I utilize the isentropic nozzle model included in PRODE PROPERTIES with HEM (Homogeneous Equilibrium Model)
my question is about discharging piping,
I have calculated (with PRODE PROPERTIES) the average density and critical speed for gas+liquid in discharging lines,
I have some values for mach number exceeding 0.5 ,
do these number exceed accepted practice ?
How can I calculate the stress on piping ?

[carlo.stenali]

while a value of 0.5 may be acceptable (that depends from several factors as density etc.)
you may evaluate F on a determined section of piping as

F = p*area + dens*area*v*v/g

as you see there is a static component (p*area)
and a dynamic component (dens*area*v*v/g)

from this you can calculate the stress.

[dbert]

mpor,
as suggested by Carlo you may accept higher mach numbers providing that noise, vibrations, stress etc. etc.
are within acceptable limits.

[carlo.stenali]

mpor,
you may find here the answer also to the other question about the higher acceptable mach number in flare networks,
for a safe design you should evaluate the maximum stress on piping.

[cstaff]

thanks Carlo

[rense]

thanks, Carlo,
it would be useful to add that formula to the Excel spreadsheet to simulate PSV discharge
(just my 2 cents..)