Modeling a Device Characterized by a Cv Value

If you have a Cv value for a valve or other device, you can model it as a component having a flow rate vs dP profile.

Use the equation below to calculate values for the component data table
{dP = \bigg[ \frac{Q}{Cv}\bigg]^2*\bigg[\frac{ \rho}{62.4}\bigg]}

Q = flow rate in gpm
Cv = valve flow coefficient
dP = pressure drop in psi
rho = fluid density (lb/ft3)

(Ref. Crane Technical Paper No. 410, pg 2-10)

For a particular valve position, take the corresponding Cv and compute the pressure drop over a range of flow rates.  It may be easiest to calculate this in Excel. Below is an example.

Then enter the data as a component in your PIPE-FLO model. Below is an example of a component with a Cv = 150.

For reference to older versions of PIPE-FLO see attachments below.


Modeling a Cv Value as a Component old.pdf