[taxalian]

Hi,
I would like to simulate the air ventilation system with a filter enclosed within a box. One side of the box has multiple inlets through which the air is coming in and the outlet is a filter surface.
So i would like to impose atmopheric conditions on the inlet like pressure and temperature, velocity is not known.
For the outlet i would like to use the filter surface as suction boundary condition using the give volumteric flow rate.
So just for the first try i use the inlet as fixed values and the outlet as flowvelocityinlet with a negative volumetric flow rate. But i get convergence problem.
Finally i would like to compare to the mass flux over the inlet and the outlet that should almost be the same.
If someone knows about any appropriate boundary condition or other tips, please let me know about that.

Thanks in advance.

[jherb]

You could use the fixedMean boundary condition for the (outward) velocity at the outlet.

[pici]

Originally Posted by taxalian

Hi,
I would like to simulate the air ventilation system with a filter enclosed within a box. One side of the box has multiple inlets through which the air is coming in and the outlet is a filter surface.
So i would like to impose atmopheric conditions on the inlet like pressure and temperature, velocity is not known.
For the outlet i would like to use the filter surface as suction boundary condition using the give volumteric flow rate.
So just for the first try i use the inlet as fixed values and the outlet as flowvelocityinlet with a negative volumetric flow rate. But i get convergence problem.
Finally i would like to compare to the mass flux over the inlet and the outlet that should almost be the same.
If someone knows about any appropriate boundary condition or other tips, please let me know about that.

Thanks in advance.

Hi Taxalian, hi to everybody
I'm beginning to work around a similar case: my medical device is very small, but I have, like you, two small inlet (2.5mm dia) and one bigger outlet, (12mm dia).
By a previous fast analysis, I found that max speed could be about 0.4 Mach, so I would like to study it using some compressible solver.
In my mind (for a stationary run) two small inlets should have a BC based only on atmospheric pressure, while outlet should have a BC based on a known Negative Volumetric Flow Rate.
Can you suggest how to assign boundary conditions ?
Many thanks
... piero