Is pressure surge in gas pipe with an emergency shutdown valve having a design pressure of 15.3 MPa likely to occur?...How can I estimate that surge? I've seen formulas from fluid transient loads but it gives the density of the fluid which we know for gas is zero. And gives me a value of zero on my surge..Which is more critical based from your experience? Is it the gas or the liquid? Your input is highly appreciated...Thnks and Cheers to all Stressers!!!

Density of a gas is never zero.

Second, by Joukowski formula, pressure due to sudden closure= density x speed of sound x fluid velocity, is it still zero?

Finally, the actual pressure differential value considering the actual closure time times flow area will it be zero? If the pressure differential is zero, we have the steday condition, when the pipings egment b/w two elbows is like a two force member. This of cousre does not happen when there is surge.

Talk to your hydraulics group about potential surge on this line.

Regards

Thanks anindya for the input. I forgot to remember the lessons from thermodynamics, which is the ideal gas law PV=mRT, where m/V is the gas density.