From actual flow rate to normal flow rate

[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

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.

 

[Achy47]

Hi there,

Thank you for sharing your work with us and asking for feedback. Your approach to converting the flow rate from actual to normal is correct. The formula you have used is a commonly used one for such conversions and should give you accurate results.

In your case, since the inlet pressure is 4 bar and the outlet pressure is 1 bar, you should use 4 bar as the actual pressure (Pa) and 1 atm (equivalent to 1.01325 bar) as the normal pressure (Pn) in the formula. This will give you the normal flow rate at the given inlet and outlet pressures.

I hope this helps and good luck with your research!