How to evacuate vapor from a pipline which is not full initially. AFT impulse 3

[bsteel]

I'm using AFT impulse, and i have pipline with no flow initially (valve closed). I have notification that vapor exists in this pipeline in steady state and so i cannot move to the transient analysis.what can i do?
I tried to use vacuum breaker valve baut it doesn't work!
Sincerly,

 

[georgeverghese]

Gerhadhl,

a) You have a point re cavitation, but we dont know yet what is the min water level in the tanks at the end of this line (ie backpressure on this BF valve)

b) Also, the operating Cv range ( for the range of flows and pumping pressures ) at this throttling valve for avoiding vapor breakout at elevation 11m is not known yet.

First choice to me would be a BF valve for 36inch in water service, and agree we move on to some other valve if we find out it cannot work based on detailed calculation results taking into account (a) and (b)