# From actual flow rate to normal flow rate

1. Nov 23, 2013

### serbring

Hi all,

I have developed a simscape model of a pressure regulator valve and I derive valve parameters from the valve datasheet. From the datasheet I get the following valve flow characteristic:

http://imagizer.imageshack.us/v2/150x100q90/c/707/3emx.jpg [Broken]

The flow rate is in normal liters, instead from simscape I get the actual flow rate, therefore I need to convert it. I found the following approximate formula to compute the normal flow rate from the actual one:

Qn = Qa x (Pa/Pn) x (Tn/Ta)

Where:

Qn is the normal flow rate
Pn is the pressure at the normal condition 1 atm
Tn is the temperature at the normal condition 293.15 K
Qa is the actual flow rate
Pa is the actual pressure
Ta is the actual temperature

Is it correct? In my case there is a valve where at the inlet there are 4bar and at the outlet there is 1 bar, so which pressure should I use for the computation of the normal flow rate?
Hopefully I have well explained my problem
Thanks.

Last edited by a moderator: May 6, 2017