Orifice with critical pressure drop

[lbvex]

I am surching for methods to calculate flowrate for hotwater through an orifice with critical pressure drop:
30 bar(e) 150 ºC - 1 bar (e) 110 ºC.

LB

 

[Eltron]

Check out thread 378-135335.

Seems like that is the info you're looking for.

 

[sailoday28]

For choked flow, that is flow which is a maximum, is independent of downstream pressure.
For two phase homogeneoujs flow, the max flow can be higher than that normally calcualted for equilibriulm isentropic conditions. It is a choked flow in a metastable state. Under that flow condition, the fluid does not flash as normally expected and typically higher flows occur.
A good example is subcooled flow thru a trap. Flows of two phase steam water have been measured to be higher than that for equilibrium flow.
Touch base with a trap vendor to get a feel for hot water flow thru an orifice. Also search for some old ASME papers on the subject.