[mumtaz ersan]

Hello Everyone,

I draw some kind of nozzle and then try to obtain pressure-drop in my drawning,

Actually in my system, 1,1 bar inlet pressure at 120lt./min air passes through from this nozzle(At 298 Kelvin),

i test the system in two different way,
My first way, i use the volume-flow;
For my inlet face, i define 0,002 m^3/sn=120lt./dak air ,
For my outlet face, i define environment pressure,
Then i define a goal for my inlet to obtain static-pressure,
And calculate DeltaP = Environment-Static Pressure in the inlet face and i obtain 84,72 Pa....

In my second way , i decide the use mass-flow because of it is compressible fluid,
For my inlet face, i define 0,0026 kg./sn mass-flow ,
For my outlet face, i define environment pressure,
Then i define a goal for my inlet to obtain static-pressure,
And calculate DeltaP = Environment-Static Pressure in the inlet face and i obtain 101,2 Pa....

I am a little bit confused,

I think it is better to trust in my second way calculation because of it is mass-flow, Am i right?????

And which way is better for these kind of examples ,to define volume-flow, mass-flow or Velocity ??????

Can anyone explain this situation?????