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[JK.HO]

Hi everyone.
I'd like to know that
How can I determine the pressure and velocity at PSV discharge elbow..

actually i'm trying to find the reaction force at discharge elbow so that determine whether it needs support or not.

In API520 Part 2 page 6 and ASME B31.1 appendix 2, there are equations to find the reaction force.
However, to find the reaction force. I need the pressure and velocity at discharge elbow.
In ASME, there are equation and coefficients to find those. but just for steam case..
How can I use that in gas case?
or are there any equation or method ?

sorry for my poor English..
Thanks

[JoeWong]

JK.HO,

To obtain pressure and velocity at the PSV discharge elbow, you may use the Isothermal equation (refer API std 521).

Subject to where your PSV discharge to, for example discharge directly to ATM, you may back calculate the pressure at the elbow from end of discharge pipe. It involve some iterations.

In many event, FLARENET is used to ease you work.