[mumtaz ersan]

Hello Everyone,

I am very new about cfd issue,i am very confused about calculating DeltaP(Pressure drop) and actually i need a help,

My first question is;
Is the inlet Pressure important for pressure-drop calculation in compressible-fluids (AIR). I mean that ; If air pass through from valve or nozzle with the same volume-flow or mass-flow but at different inlet pressures(For example; in my first test 2,5 bar inlet pressure at 120lt./min and in my second test 1,1 bar inlet pressure at 120lt./min )At the end, what can we say about their DeltaP(pressure-drop),For these two test ; Will their DeltaP(Pressure-Drop) be same or not ??????

My Second question is;
The formula for the ideal-gas, P=d*R*T ,
in this formula P symbolize which pressure ??? Static-pressure or Total-Pressure????

My third and last question is;

How do cfd programs calculate total-pressure and static pressure and density???? They calculate by the help of ideal-gas equation(P=d*R*T) or different way????? For example i define air at 120 lt./min at 298 Kelvin for inlet in a nozzle for calculating pressure-drop, and i define enviroment-pressure for outlet in solid-works flow simulation by the way my inlet dia is 18.95 mm.

Program gives me for a result;
Density : 1,18
Total Pressure :101407,47 pascal
Static Pressure :101427,47
Dynamic pressure : 30,11

If i calculate total-pressure by manually i find:

P=1.18*0,287*298 100.92 kpa==100920 Pascal and it isn't equal to total-pressure which is taken from program.So i think i miss sth....

P.S i know this forum topic isn't for solidworks-flow simulation but i watch few tutorials on the internet and the other programs use the same method with solidworks flowsimulation for calculating pressure-drop so i decide to write here for the purpose of reaching more people.....

I hope i didn't do wrong thing to write here,

And i hope explaine my question...

Can anyone explain this questions at least one of them????

Thanks for everyone...