centaur21
Electrical
- Jun 5, 2006
- 44
Maybe I'm missing something but I've gone round and round trying to come up with a way to solve the three (3) equations below.
Let's say I calculate Pvc (pressure at vena contracta, psia) using the formula Pvc = FF * Pv. That's ok but when you insert Pvc into the FL (Liquid Pressure recovery factor) equation, you're still missing the ∆P value because in this case, the ∆P in the FL equation is the ∆P choked value (∆Pch) and not just ∆P (i.e. P1 - P2) which puts me at a dead end.
I realize that control valve manufacturers provide the FL and from there you can solve the other equations, but is the only way to solve for all three equations below is to be given the value for one of the three equations? For these equations, the FL value would have to be the one provided. I would greatly appreciate any input on this question. Thanks!
Let's say I calculate Pvc (pressure at vena contracta, psia) using the formula Pvc = FF * Pv. That's ok but when you insert Pvc into the FL (Liquid Pressure recovery factor) equation, you're still missing the ∆P value because in this case, the ∆P in the FL equation is the ∆P choked value (∆Pch) and not just ∆P (i.e. P1 - P2) which puts me at a dead end.
I realize that control valve manufacturers provide the FL and from there you can solve the other equations, but is the only way to solve for all three equations below is to be given the value for one of the three equations? For these equations, the FL value would have to be the one provided. I would greatly appreciate any input on this question. Thanks!
