Analytical Ventury design approach for finding Cd (coeff.dis) value

[thought2007]

Hello,

Would like to know whether the following analytical ventury design approach is correct or Incorrect to find Coefficient of discharge.

Following are the available design data to find Cd

1.Geometry of flow path is defined (throat dia
Diametrical ratio "Beta")
2.Upward flow data is available ( Flow rate,Inlet
pressure,density of fluid,Kinemtic viscosity of fluid)
3.Required Maximum pressure drop at downward flow is
available

Design approach

1.Using ventury equation(ISO standard) theorotical flow
rate (Qth)is deteremined

Qth=Throat area*Sqrt of 2*density*Pressure
drop/density*Sqrt of 1-Diametrical ratio^4

2.Reynolds number is determined using Qth.This Renolds
number used in the calibrated curve(Cd Vs Renolds Number)
for finding Cd value.
3.From "Cd" value updated theorotical flow rate(Qthu)is
determined.
4.Flow rate(Qa)& pressure drop at downward section is
determined using analysis tool CF design
5.Finally Coefficient of discharge is defined as

Cd=Qthu/Qa

Thanks
John