Orifice Flow/Pipe Entrance Loss Coefficient Question
Orifice Flow/Pipe Entrance Loss Coefficient Question
(OP)
Geetings,
Originally posted this on the Fluid Mechanics forum but no activity so I thought I would try here...
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 a pipe 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.
Struggled then with the formula given just below 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 small hole in a tank wall.
How do we make the leap to a pipe entrance loss K of 0.5? Wouldn't a hole in a tank wall be equivalent to an orifice with a beta ratio = 0?
Thanks in advance.
JoeChem
Originally posted this on the Fluid Mechanics forum but no activity so I thought I would try here...
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 a pipe 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.
Struggled then with the formula given just below 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 small hole in a tank wall.
How do we make the leap to a pipe entrance loss K of 0.5? Wouldn't a hole in a tank wall be equivalent to an orifice with a beta ratio = 0?
Thanks in advance.
JoeChem





RE: Orifice Flow/Pipe Entrance Loss Coefficient Question
Good luck,
Latexman
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Orifice Flow/Pipe Entrance Loss Coefficient Question
But i think that the "beta method" is means for flow measurement orifices, where the D/Do ration is close to 1? So in general the beta method can not be used for holes or exits e.g. from tanks?
Best regards
Morten