flow through a orifice

[peng80]

Guys,

Hope you can help me out with a calculation.

I have a system with unstabilized crude. If there were a accidental release of hydrocarbons from this system, from a hole (for example 1 cm diameter), how can the flow through this hole be calculated?

I know how to calculate the flow if this was a gas or liquid service, using standard orifice sizing calcs. With a unstabilized crude service, I am not sure how to calculate due to flashing.

The system can be assumed at such pressure that the flow would be sonic (for example 40 barg system pressure, and release to atmospheric pressure)


Thanks!

 

[PaoloPemi]

it doesn't appear an easy task, cause the difficulty to determine two-phase flow regime, one could assume the two-phase mixture as homogeneous and apply a homogeneous equilibrium (HEM) or the homogeneous nonequilibrium (HNE) but in several cases you could obtain unrealistic results.
For rupture disks I have created a simple Excel page based on a paper of Fauske, Sizing of Rupture disks for two-phase flow, the flow was determined as W=Kd*A*G where Kd is the discharge coefficient, A the area and G the two-phase mass flux, the paper gives simple correlations to calculate G in different cases. A more complex approach is the Omega method, in general for this matter I would recommend the papers of Fauske and Leung.

 

[dcasto]

search restrictive orifice
or
Thread=189979