JoeChem
Chemical
- Dec 9, 2002
- 50
Geetings,
Was recently trying to calculate an accidental discharge of liquid from a tank (small hole) and was scratching my head about some things in Crane TP410 and was hoping to get some clarification. I was not sure if I should approach the leak rate calculation using an orifice equation or as an entrance loss equation. This really boiled down to selecting a C for the orifice or a K for an entrance loss
When considering a flow coefficient for an orifice, as the beta ratio decreases the approach Reynolds number decreases and C approaches 0.5 as shown on the graph on page A-20. All is good.
Struggled then with the formula given to calculate K for an orifice:
K = (1-beta^2)/(C^2 x beta^4)
K values begin to increase rapidly as beta decreases. The denominator is essentially 0 for low beta values, i.e., a pinhole in a tank wall.
How do we get to an entrance loss K of 0.5?
Thanks in advance.
JoeChem
Was recently trying to calculate an accidental discharge of liquid from a tank (small hole) and was scratching my head about some things in Crane TP410 and was hoping to get some clarification. I was not sure if I should approach the leak rate calculation using an orifice equation or as an entrance loss equation. This really boiled down to selecting a C for the orifice or a K for an entrance loss
When considering a flow coefficient for an orifice, as the beta ratio decreases the approach Reynolds number decreases and C approaches 0.5 as shown on the graph on page A-20. All is good.
Struggled then with the formula given to calculate K for an orifice:
K = (1-beta^2)/(C^2 x beta^4)
K values begin to increase rapidly as beta decreases. The denominator is essentially 0 for low beta values, i.e., a pinhole in a tank wall.
How do we get to an entrance loss K of 0.5?
Thanks in advance.
JoeChem
