Hi there,

I have a model which is a quit complex building of pipes, which are in parallel and in serial and in additional with some flow resistance (ellbows and so on). At the end I have a outlet-lit, which represents a fan.

Now I like to get the pressure drop at this lit, so I can choose the proper fan in reality.

On the otherside of the model, I have some other lits (which represents several inlets to the parallel pipes, and opened to the ambient surrounding).

By now I tried to use following setup:

- internal analysis

- fluid: air; laminar and turbulent

- adiabatic wall; roughness 10 µm

- standard thermodynamic parameters; no velocity

this boundary condition:

- Inlet lit: ambient pressure

- outlet lit: constant flow rate

and this goals:

- total pressure at inlet and outlet

(here I am not sure, if I choosed the proper pressure (static?), and do I need to set a velocity goal as well, since this is a significant value for the pressure?)

in the next step, i vary the flowrate to create a pressure - flowrate - chart (the characteristic curve of that model).

I never expected to get a value which corresponds to 100 % to the real measurement.

But as I now measured, it doesn`t correspond at all.

So what kind of mistake did i make?

Where is my logical failure?

Thanks in advance.