[iggythewiggy]

Good evening,

I'm currently working on a project with engine nacelle where I'm trying to find out what is the mass flow rate of the flow inside of the nacelle and extrapolate this data outside to confirm my data.

I tried using mass flow rate inlet and having outflow.
I'm using specific values of 15 000kg/s and my outflow is set to be 1.

Any suggestions are welcome as I cannot find any solutions at the moment.

Thank you very much

[vinerm]

I am afraid there appears to be some ambiguity in your description. You are applying mass flow rate of 15000 kg/s at the inlet. If that is the only inlet, mass flow rate is not going to change anywhere.

Prefer using pressure outlet instead of outflow until and unless you are very sure that the flow is always in the outward direction at the outlet.

[iggythewiggy]

looking at this would I need to select anything else as well with it?

[iggythewiggy]

see attached picture

[vinerm]

No more information is required. However, do note that the pressure is gauge pressure and not absolute pressure.

[iggythewiggy]

so if my pressure at inlet should be 2.1945e+9 Pa what would be the gauge pressure? Is it just -2194500101 Pa?

[vinerm]

Gauge pressure is difference between absolute and surroundings or atmospheric pressure. Fluent uses 101325 Pa, i.e., 1 atm. as operating pressure. So, if your pressure is 111325 Pa absolute, then gauge would be 10000 Pa.

[iggythewiggy]

Does the pressure in inlet and outlet needs to be different than in gauge value or same across?

[vinerm]

Flow is driven by pressure if there is no moving boundary. If you have same pressure at the inlet and outlet, then there won't be any flow. If you apply mass flow rate at the inlet and pressure at the outlet, then it will automatically maintain the pressure drop and mass flow rate.