Calclating Cv from Orifice Diameter

[NitroDude]

Does anyone know the formula for calculating Cv when orifice plate diameter (straight edged) and plate thickness is known? I routinely need to size orifice for Compressed Air and Nitrogen Gas. I would also know the temperature, pressure, specific gravity of the fluid medium. I have a program already written to size valves etc. based on a known Cv value and would like to calculate Cv from orifice diameter. Can anyone help?

 

[israelkk]

see lower part of the page:

http://www.theleeco.com/LEEWEB2.NSF...2080c790388543948525689b00654b38!OpenDocument